Multi-beam exposure apparatus using a multi-axis electron lens, electron lens convergencing a plurality of electron beam and fabrication method of a semiconductor device

ABSTRACT

An electron beam exposure apparatus for exposing a wafer with a plurality of electron beams includes a multi-axis electron lens having a plurality of lens openings operable to converge the electron beams independently of each other, the plurality of lens openings having different shapes.

This is a counterpart application of a Japanese patent applications2000-102619, filed on Apr. 4, 2000, 2000-251885, filed on Aug. 23, 2000,and 2000-342660, filed on Oct. 3, 2000, the contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a multi-electron-beam exposureapparatus, a multi-axis electron lens, a fabrication method of themulti-axis electron lens and a fabrication method of a semiconductordevice.

2. Description of the Related Art

Conventionally, it is known an electron-beam exposure apparatus capableof exposing a wafer with a plurality of electron beams in order to forma semi-conductor device. For example, an electrons-beam exposureapparatus including an electron lens having a pair of magnetic platesplaced in parallel relationship with each other is disclosed in U.S.Pat. No. 3,715,580 or in U.S. Pat. No. 4,209,702. The pair of magneticplates has a plurality of through holes at places corresponding to eachother for respectively having the plurality of electron beams passtherethrough in order for focusing images.

As semi-conductor devices are becoming more and more minute structures,exposure apparatuses for forming lines of the semi-conductor devices arerequired to have high accuracy in focusing images. Therefore, it ishighly expected that an electron-beam exposure apparatuses capable ofexposing a plurality of electron beams for forming patterns of lines ofthe semi-conductor devices be commercially produced. In order to producequantity of semi-conductor devices by such the electron-beam exposureapparatus, preferably, the focusing points of the plurality of electronbeams should be adjusted on the wafer become.

The conventional electron beam exposure apparatus disclosed in abovepatents corrects the focusing point of the electron beams by usingexciting coils provided between the pair of magnetic plates. However, asfor the conventional electron beam exposure apparatus, in case that themagnetic fields formed in each of the plurality of through holes aredispersed largely, it is difficult to correct the focusing point of theelectron beams uniformly. Especially, as the size of the wafer becomeslager, the electric field strength formed in the through holes at theedge of the electron lens becomes more different from that at the centerof the electron lens.

Therefore, as for the conventional electron beam exposure apparatus, thefocusing points of the plurality of electron beams cannot be adjusted onthe wafer. Thus, this type of electron-beam exposure apparatus cannotshow accuracy in focusing the images. This fact prevents theelectron-beam exposure apparatus exposing a plurality of electron beamsfrom commercially produced.

SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention to provide amulti-beam exposure apparatus using a multi-axis electron lens, amulti-axis electron lens and a fabrication method of a semiconductordevice, which is capable of overcoming the above drawbacks accompanyingthe conventional art. The above and other objects can be achieved bycombinations described in the independent claims. The dependent claimsdefine further advantageous and exemplary combinations of the presentinvention.

According to the first aspect of the present invention, an electron beamexposure apparatus for exposing a wafer with a plurality of electronbeams, comprising a multi-axis electron lens having a plurality of lensopenings operable to converge said plurality of electron beamsindependently of each other by allowing said plurality of electron beamsto pass therethrough, respectively, said plurality of lens openingshaving different shapes.

The multi-axis electron lens may include a plurality of magneticconductive members having a plurality of openings arranged to besubstantially parallel to each other, said plurality of openings formingsaid lens openings.

The magnetic conductive members may include said openings havingdifferent sizes.

At least one of said plurality of magnetic conductive members mayinclude cut portions provided in outer peripheries of said openings.

The cut portions may have different sizes.

At least one of said magnetic conductive members may include a magneticconductive projection provided on a surface thereof between apredetermined one of said openings and another opening adjacent to saidpredetermined opening, said magnetic conductive projection projectingfrom said surface of said at least one of said magnetic conductivemembers.

The electron beam exposure apparatus may further comprise alens-intensity adjuster including: a substrate provided to besubstantially parallel to said multi-axis electron lens; and alens-intensity adjusting unit, provided on said substrate, operable toadjust the lens intensity of said multi-axis electron lens applied tosaid electron beams passing through said lens openings, respectively.

The lens-intensity adjusting unit may include an adjusting electrodeprovided to surround said electron beams from said substrate to saidlens opening, said adjusting electrode being insulated from saidmagnetic conductive members.

The lens-intensity adjusting unit may include a plurality of adjustingelectrodes provided to surround said electron beams, respectively, fromsaid substrate to said lens opening.

The lens-intensity adjusting unit may further include a means operableto apply different voltages to said plurality of adjusting electrodes.

The lens-intensity adjusting unit may further include an adjusting coiloperable to adjust magnetic field intensities in said lens openings,said adjusting coil being provided to surround said electron beams fromsaid substrate along a direction in which said electron beams areradiated.

The multi-axis electron lens may further include a non-magneticconductive member having a plurality of through holes, said non-magneticconductive member being provided between said plurality of magneticconductive members, said plurality of openings of said magneticconductive members and said plurality of through holes forming togethersaid plurality of lens openings.

The multi-axis electron lens may further include a coil part having acoil provided in an area surrounding said magnetic conductive membersfor generating a magnetic field and a coil magnetic conductive memberprovided in an area surrounding said coil.

The coil magnetic conductive member may be formed from a material havinga different magnetic permeability from that of a material for saidplurality of magnetic conductive members.

The electron beam exposure apparatus may further comprise at least onefurther multi-axis electron lens operable to reduce cross sections ofsaid electron beams.

The electron beam exposure apparatus may further comprise an electronbeam shaping unit that comprises: a first shaping member having aplurality of first shaping openings operable to shape said plurality ofelectron beams; a first shaping-deflecting unit operable to deflect saidplurality of electron beams after passing through said first shapingmember, independently of each other; and a second shaping member havinga plurality of second shaping openings operable to shape said pluralityof electron beams after passing through said first shaping-deflectingunit to have desired shapes.

The electron beam shaping unit may further include a secondshaping-deflecting unit operable to deflect said plurality of electronbeams deflected by said first shaping-deflecting unit independently ofeach other toward a direction substantially perpendicular to a surfaceof said wafer onto which said electron beams are incident, wherein saidelectron beam shaping unit allows said plurality of electron beamsdeflected by said second shaping-deflecting unit to pass through saidsecond shaping member so as to shape said electron beams to have saiddesired shapes.

The second shaping member may include a plurality of shaping-memberillumination areas onto which said electron beams deflected by thesecond shaping-deflecting unit are incident, and said second shapingmember includes said second shaping openings and other openings havingdifferent sizes from sizes of said second shaping openings in saidshaping-member illumination area.

The electron beam exposure apparatus may further comprise: a pluralityof electron guns operable to generate said plurality of electron beams;and a further multi-axis electron lens operable to converge saidplurality of electron beams generated by said plurality of electron gunsto make said converged electron beams incident on said first shapingmember, wherein said first shaping member divides said electron beamsafter passing through said further multi-axis electron lens.

The electron beam exposure apparatus may comprise a plurality ofmulti-axis electron lenses having said lens openings.

The multi-axis electron lens may further include a plurality of dummyopenings through which no electron beam passes.

The plurality of dummy openings may be provided in outer peripheries ofan area where said plurality of lens openings are arranged.

According to the second aspect of the present invention, an electronlens for converging a plurality of electron beams independently of eachother, comprising a plurality of magnetic conductive members arranged tobe substantially parallel to each other, said magnetic conductivemembers having a plurality of openings, wherein said plurality ofopenings of said magnetic conductive members form a plurality of lensopenings allowing said plurality of electron beams to pass therethrough,respectively, to converge said electron beams independently of eachother, said lens openings having different shapes.

According to the third aspect of the present invention, a fabricationmethod of a semiconductor device on a wafer, comprising: performingfocus adjustments for said plurality of electron beams independently ofeach other by using a multi-axis electron lens having a plurality oflens openings having different shapes that allow a plurality of electronbeams to pass therethrough, respectively, to converge said electronbeams independently of each other; and exposing a pattern onto saidwafer by illuminating said wafer with said plurality of electron beams.

The summary of the invention does not necessarily describe all necessaryfeatures of the present invention. The present invention may also be asub-combination of the features described above The above and otherfeatures and advantages of the present invention will become moreapparent from the following description of the embodiments taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an electron beam exposure apparatus 100 according to anembodiment of the present invention.

FIG. 2 schematically shows an arrangement of a voltage controller 520.

FIG. 3 shows another example of an electron beam shaping unit.

FIG. 4 shows an exemplary structure of a blanking electrode array 26.

FIG. 5 shows a cross section of the blanking electrode array 26.

FIG. 6 schematically shows a structure of a first shaping deflectingunit 18.

FIGS. 7A, 7B and 7C schematically show an exemplary arrangement of thedeflector 184.

FIG. 8 shows a first multi-axis electron lens 16 that is an electronlens according to an embodiment of the present invention.

FIG. 9 shows another exemplary first multi-axis electron lens 16.

FIG. 10 shows another exemplary first multi-axis electron lens 16.

FIG. 11 shows another exemplary first multi-axis electron lens 16.

FIGS. 12A and 12B show examples of the cross section of the firstmulti-axis electron lens 16.

FIG. 13 shows another exemplary multi-axis electron lens.

FIGS. 14A and 14B show other examples of the lens part 200.

FIGS. 15A and 15B show another example of the lens part 202.

FIGS. 16A, 16B and 16C shows other examples of the lens part 202.

FIGS. 17A and 17B show an example of a lens-intensity adjuster foradjusting the lens intensity of the multi-axis electron lens.

FIGS. 18A and 18B show another exemplary lens-intensity adjuster.

FIGS. 19A and 19B show an exemplary arrangement of a firstshaping-deflecting unit 18 and a blocking unit 600.

FIG. 20 shows a specific example of first and second blocking electrodes604 and 610.

FIGS. 21A and 21B show another example of the first shaping-deflectingunit 18 and the blocking unit 600.

FIG. 22 shows another exemplary arrangement of the firstshaping-deflecting unit 18.

FIGS. 23A and 23B show an exemplary arrangement of a deflecting unit 60,a fifth multi-axis electron lens 62 and a blocking unit 900.

FIG. 24 shows an electric field blocked by the blocking unit 600 or 900.

FIG. 25 shows an example of the first and second shaping members 14 and22.

FIGS. 26A, 26B, 26C, 26D and 26E show exemplary pattern openings 566 ofthe second shaping member 22.

FIG. 27 shows an exemplary arrangement of a controlling system 140 shownin FIG. 1.

FIG. 28 shows details of components included in an individualcontrolling system 120.

FIG. 29 shows an example of a backscattered electron detector 50.

FIG. 30 shows another exemplary backscattered electron detector 50.

FIG. 31 shows another exemplary backscattered electron detector 50.

FIG. 32 shows another exemplary backscattered electron detector 50.

FIG. 33 shows an electron beam exposure apparatus 100 according toanother embodiment of the present invention.

FIGS. 34A and 34B show an exemplary arrangement of the electron beamgenerator 10.

FIGS. 35A and 35B show an exemplary arrangement of the blankingelectrode array 26.

FIGS. 36A and 36B shows an exemplary arrangement of the firstshaping-deflecting unit 18.

FIG. 37 illustrates an exposure operation for a wafer 44 on the electronbeam exposure apparatus 100 according to the second embodiment.

FIGS. 38A and 38B schematically show deflection operations of the maindeflecting unit 42 and the sub-deflecting unit 38 in the exposureprocess.

FIG. 39 shows an example of the first multi-axis electron lens 16.

FIGS. 40A and 40B show examples of the cross section of the firstmulti-axis electron lens 16.

FIG. 41 shows an electron beam exposure apparatus 100 according to stillanother embodiment of the present invention.

FIGS. 42A and 42B show an exemplary arrangement of the BAA device 27.

FIGS. 43A and 43B show the third multi-axis electron lens 34.

FIGS. 44A and 44B show the deflecting unit 60. The

FIGS. 45A through 45G illustrate an exemplary fabrication process of thelens part 202 of the multi-axis electron lens according to an embodimentof the present invention.

FIGS. 46A through 46E illustrate exemplary processes for formingprojections 218.

FIGS. 47A and 47B illustrate another example of the fabrication methodof the lens part 202.

FIGS. 48A, 48B and 48C illustrate a fixing process for fixing the coilpart 200 and the lens part 202.

FIG. 49 is a flowchart of processes for fabricating a semiconductordevice from a wafer according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described based on the preferred embodiments,which do not intend to limit the scope of the present invention, butexemplify the invention. All of the features and the combinationsthereof described in the embodiment are not necessarily essential to theinvention.

FIG. 1 shows an electron beam exposure apparatus 100 according to anembodiment of the present invention. The electron beam exposureapparatus 100 includes an exposure unit 150 for performing apredetermined exposure process for a wafer 44 with electron beams and acontrolling system 140 for controlling operations of respectivecomponents included in the exposure unit 150.

The exposure unit 150 includes: a body 8 provided with a plurality ofexhaust holes 70; an electron beam shaping unit which can emit aplurality of electron beams and shape a cross-sectional shape of eachelectron beam so that each electron beam has a desired shape; anillumination switching unit which can independently switch for eachelectron beam whether or not the electron beam is cast onto the wafer44; and an electron optical system including a wafer projection systemwhich can adjust the orientation and size of a pattern image transferredonto the wafer 44. In addition, the exposure unit 150 includes a stagesystem having a wafer stage 46 on which the wafer 44, onto which thepattern is to be transferred by exposure, can be placed and awafer-stage driving unit 48 which can drive the wafer stage 46.

The electron beam shaping unit includes an electron beam generator 10which can generate a plurality of electron beams, an anode 13 whichallows the generated electron beams to be radiated, a slit cover 11having a plurality of openings for shaping the cross-sectional shapes ofthe electron beams by allowing the electron beams to pass there-through,a first shaping member 14, a second shaping member 22, a firstmulti-axis electron lens 16 which can converge the electron beams toadjust focal points of the electron beams independently of each other, afirst lens-intensity adjuster 17 which can adjust the lens intensitywhich is the force that the magnetic field, which is formed in each lensopening of the first multi-axis electron lens 16, gives to the electronbeam passing through the lens opening,

The electron beam generator 10 includes an insulator 106, cathodes 12which can generate thermoelectrons, and grids 102 formed to surround thecathodes 12 so as to stabilize the thermoelectrons generated by thecathodes 12. It is preferable that the cathodes 12 and the grids 102 areelectrically insulated from each other. In this example, the electronbeam generator 10 forms an electron gun array by having a plurality ofelectron guns 104 arranged at a predetermined interval on the insulator106.

It is desirable that the slit cover 11 and the first and the secondshaping member 14 and 22 have grounded metal films such as platinumfilms, on surfaces thereof onto which the electron beams are cast. It isalso desirable that each of the slit covers 11, the first shaping member14 and the second shaping member 22 include a cooling unit forsuppressing the increase in the temperature caused by the incidentelectron beams.

The openings included in each of the slit covers 11, the first shapingmember 14 and the second shaping member may have cross-sectional shapeseach of which becomes wider along the radiated direction of the electronbeams in order to allow the electron beams to pass efficiently.Moreover, the openings of each of the slit covers 11, the first shapingmember 14 and the second shaping member 22 are preferably formed to berectangular.

The illumination switching unit includes: a second multi-axis electronlens 24 which can converge a plurality of electron beams independentlyof each other and adjust focal points thereof; a second lens-intensityadjuster 25 which can independently adjust the lens-intensity in eachlens opening of the second multi-axis electron lens 24; a blankingelectrode array 26 which switches for each of the electron beams whetheror not the electron beam is allowed to reach the wafer 44 by deflectingthe electron beam independently of each other; and an electron beamblocking member 28 that has a plurality of openings allowing theelectron beams to pass there-through and can block the electron beamsdeflected by the blanking electrode array 26. The openings of theelectron beam blocking member 28 may have cross-sectional shapes each ofwhich becomes wider along the illumination direction of the electronbeams in order to allow the electron beams to efficiently passthere-through.

The wafer projection system includes: a third multi-axis electron lens34 which can converge a plurality of electron beams independently ofeach other and adjust the rotations of the electron beams to be incidentonto the wafer 44; a third lens-intensity adjuster 35 which canindependently adjust the lens intensity in each lens opening of thethird multi-axis electron lens 34; a fourth multi-axis electron lens 36which can converge a plurality of electron beams independently of eachother and adjust the reduction ratio of each electron beam to beincident onto the wafer 44; a fourth lens-intensity adjuster 37 whichcan independently adjust the lens intensity in each of lens openings ofthe fourth multi-axis electron lens 36; a deflecting unit 60 which candeflect a plurality of electron beams independently of each other todirect desired portions on the wafer 44; and a fifth multi-axis electronlens 62 which can function as an objective lens for the wafer 44 byconverging a plurality of electron beams independently of each other. Inthis example, the third multi-axis electron lens 34 and the fourthmulti-axis electron lens 36 are integrated with each other. In analternative example, however, the third and fourth multi-axis electronlenses may be formed as separate components.

The controlling system 140 includes a general controller 130, amulti-axis electron lens controller 82, a backscattered electronprocessing unit 99, a wafer-stage controller 96 and an individualcontroller 120 which can control exposure parameters for each of theelectron beams. The general controller 130 is, for example, a workstation and can control the respective controllers included in theindividual controller 120. The multi-axis electron lens controller 82controls currents to be respectively supplied to the first multi-axiselectron lens 16, the second multi-axis electron lens 24, the thirdmulti-axis electron lens 34 and the fourth multi-axis electron lens 36.The backscattered electron processing unit 99 receives a signal based onthe amount of backscattered electrons or secondary electrons detected ina backscattered electron detector 50 and notifies the general controller130 that the backscattered electron processing unit 99 received thesignal. The wafer-stage controller 96 controls the wafer-stage drivingunit 48 so as to move the wafer stage 46 to a predetermined position.

The individual controller 120 includes an electron beam controller 80for controlling the electron beam generator 10, a shaping-deflectorcontroller 84 for controlling the first and second-shaping deflectingunits 18 and 20, a lens-intensity controller 88 for controlling thefirst, second, third and fourth lens-intensity adjusters 17, 25, 35 and37, a blanking electrode array controller 86 for controlling voltages tobe applied to deflection electrodes included in the blanking electrodearray 26, and a deflector controller 98 for controlling voltages to beapplied to electrodes included in the deflectors of the deflecting unit60.

Next, the operation of the electron beam exposure apparatus 100 in thepresent embodiment is described. First, the electron beam generator 10generates a plurality of electron beams. The generated electron beamspass the anode 13 to enter a slit-deflecting unit 15. Theslit-deflecting unit 15 adjusts the incident positions on the slit cover11 onto which the electron beams that have passed through the anode 13are incident.

The slit cover 11 can block a part of each electron beam so as to reducethe area of the electron beam incident on the first shaping member 14,thereby shaping the cross section of the electron beam to have apredetermined size. The thus shaped electron beam is incident on thefirst shaping member 14 in which it is further shaped. Each of theelectron beams that have passed through the first shaping member 14 hasa rectangular cross section in accordance with a corresponding one ofthe openings included in the first shaping member 14.

The first multi-axis electron lens 16 converges the electron beams thathave been shaped to have rectangular cross sections by the first shapingmember 14 independently of other electron beams, thereby the focusadjustment of the electron beam with respect to the second shapingmember 22 can be performed for each electron beam. The firstlens-intensity adjuster 17 adjusts the lens intensity in each lensopening of the first electron lens 16 in order to correct the focalpoint of the corresponding electron beam incident on the lens opening.

The first shaping deflecting unit 18 deflects each of the electron beamshaving the rectangular cross sections independently of the otherelectron beams, in order to make the electron beams incident on desiredpositions on the second shaping member 22. The second shaping deflectingunit 20 further deflects the thus deflected electron beams independentlyof each other in a direction approximately perpendicular to the secondshaping member 22, thereby making adjustment in such a manner that theelectron beams are incident on the desired positions of the secondshaping member 22 approximately perpendicular to the second shapingmember 22. The second shaping member 22, having a plurality ofrectangular openings, further shapes the electron beams incident thereonin such a manner that the electron beams have desired rectangular crosssections respectively when being incident on the wafer 44. In thisexample, the first shaping deflecting unit 18 and the second shapingdeflecting unit 20 are provided on the same substrate as shown in FIG.1. In an alternative example, however, the first and second shapingdeflecting units 18 and 20 may be formed separately.

The second multi-axis electron lens 24 converges the electron beams thathave passed through the second shaping deflecting unit 20 independentlyof each other so as to perform the focus adjustment of the electron beamwith respect to the blanking electrode array 26 for each electron beam.The second lens-intensity adjuster 25 adjusts the lens intensity in eachlens opening of the second multi-axis electron lens 24 in order tocorrect the focal point of each electron beam incident onto the lensopening. The electron beams having the focal points adjusted by thesecond multi-axis electron lens 24 then pass through a plurality ofapertures included in the blanking electrode array 26, respectively.

The blanking electrode array controller 86 controls whether or notvoltages are applied to deflection electrodes provided in the vicinityof the respective apertures of the blanking electrode array 26. Based onthe voltages applied to the deflection electrodes, the blankingelectrode array 26 switches for each of the electron beams whether ornot the electron beam is to be incident on the wafer 44. When thevoltage is applied, the electron beam passing through the correspondingaperture is deflected. Thus, the electron beam cannot pass acorresponding opening of the electron beam blocking member 28, so thatit cannot be incident on the wafer 44. When the voltage is not applied,the electron beam passing through the corresponding aperture is notdeflected, so that it can pass through the corresponding opening of theelectron beam blocking member 28. Thus, the electron beam can beincident on the wafer 44.

The third multi-axis electron lens 34 adjusts the rotation of theelectron beams that have passed through the blanking electrode array 26.More specifically, the third multi-axis electron lens 34 adjusts therotation of the image of the electron beams illuminated onto the wafer44. The third lens-intensity adjuster 35 also adjusts the lens intensityin each lens opening of the third multi-axis electron lens 36 in orderto make the rotations of the images of the respective electron beamsincident on the third multi-axis electron lens 34 uniform.

The fourth multi-axis electron lens 36 reduces the illumination diameterof each of the electron beams incident thereon. The fourthlens-intensity adjuster 37 adjusts the lens intensity in each lensopening of the fourth multi-axis electron lens 36, thereby making thereduction rates of the electron beams substantially the same. Among theelectron beams that have passed through the third multi-axis electronlens 34 and the fourth multi-axis electron lens 36, only the electronbeam to be incident onto the wafer 44 passes through the electron beamblocking member 27, so as to enter the deflecting unit 60.

The deflector controller 98 controls a plurality of deflectors includedin the deflecting unit 60 independently of each other. The deflectingunit 60 deflects the electron beams incident on the deflectors thereofindependently of each other, in such a manner that the deflectedelectron beams are incident on the desired positions on the wafer 44.The fifth multi-axis electron lens 62 further adjusts the focus of theelectron beams incident on the deflecting unit 60 with respect to thewafer 44 independently of each other. Then, the electron beams that havepassed through the deflecting unit 60 and fifth multi-axis electron lens62 can be incident on the wafer 44.

During the exposure process, the wafer-stage controller 96 moves thewafer stage 48 in predetermined directions. The blanking electrode array86 determines the apertures that allow the electron beams to passthere-through and performs electric-power control for the respectiveapertures. In accordance with the movement of the wafer 44, theapertures allowing the electron beams to pass there-through are changedand the electron beams that have passed through the apertures arefurther deflected by the deflecting unit 60, thereby the wafer 44 isexposed to have a desired circuit pattern transferred.

The multi-axis electron lens of the present invention converges aplurality of electron beams independently of each other. Thus, althougha cross over is formed for each electron beam, all the electron beams asa whole do not have a crossover. Therefore, even in a case where thecurrent density of each electron beam is increased, the electron beamerror, which may cause a shift of the focus or position of the electronbeam due to coulomb interaction, can be decreased. Accordingly, thecurrent density of each electron beam can be reduced, greatly shorteningthe exposure time.

FIG. 2 schematically shows an arrangement of a voltage controller 520which can apply a predetermined voltage to the electron beam generator10. The voltage controller 520 includes a base power source 522 thatgenerates the predetermined voltage, and adjusting power sources 524that increase or reduce the predetermined voltage and apply theincreased or reduced voltages to the respective cathodes 12.

The voltage controller 520 controls an acceleration voltage of eachelectron beam by controlling the voltage to be applied to the cathode 12based on an instruction from the electron beam controller 80. It ispreferable that the voltage controller 520 may control the accelerationvoltage of each electron beam by applying, to the cathode 12 of thecorresponding electron gun, the voltage that depends on themagnetic-field intensity applied to the electron beam by the multi-axiselectron lenses 16, 24, 34, 36 and 62.

Moreover, it is preferable that the voltage controller 520 controls theacceleration voltages of the respective electron beams by applyingdifferent voltages to the cathodes of the electron guns, the voltagesbeing determined in such a manner that the positions of the focal pointsof the respective electron beams to be incident on the wafer 44 areequal to each other. Furthermore, the voltage controller 520 may furthercontrol the acceleration voltages of the electron beams by applyingdifferent voltages to the cathodes 12 of the electron guns in such amanner that predetermined sides of the cross sections of the respectiveelectron beams to be incident on the wafer 44 are substantially parallelto each other.

In this example, the base power source 522 generates a voltage of 50 kV.Each of the adjusting power sources 524 increases or lowers the voltagegenerated by the base power source 522 in accordance with themagnetic-field intensities generated in the lens openings of themulti-axis electron lenses 16, 24, 34, 36 and 62 through which theelectron beam generated by the corresponding cathode 12 passes, so thatthe adjusted voltage is applied to the corresponding cathode 12. In acase where the magnetic-field intensity in the lens opening on thecenter of the multi-axis electron lens is weaker than that in the outerperiphery of the multi-axis electron lens by 3%, for example, theacceleration voltage of the cathode 12 for generating an electron beamthat is to pass through the lens opening on the center of the multi-axiselectron lens is increased by 3%.

The electron beam controller 80 can adjust a time period for which eachof the electron beams passes through the lens opening by controlling theacceleration voltage for the electron beam, even if the intensity of themagnetic field in the lens opening of the multi-axis electron lens isvaried. Thus, the electron beam controller 80 can control effects of themagnetic field on the respective electron beams in the lens openings.Also, the electron beam controller 80 can control the focal pointpositions of the electron beams with respect to the wafer 44 and therotation of the exposure images of the electron beams to be incident onthe wafer 44.

FIG. 3 shows another example of the electron beam shaping unit. Theelectron beam shaping unit of this example further includes a firstillumination multi-axis electron lens 510 and a second illuminationmulti-axis electron lens 512 for converging the electron beams generatedby the electron beam generator 10 independently of each other so as toallow the converged electron beams to be incident on the first shapingmember 14. The first and second illumination multi-axis electron lenses510 and 512 are provided between the electron beam generator 10 and thefirst shaping member 14.

The number of the lens openings included in each of the first and secondillumination multi-axis electron lenses 510 and 512 is preferably lessthan the number of the lens openings of the first multi-axis electronlens 16. It is also preferable that the opening size of the lens openingof the first and second illumination multi-axis lenses 510 and 512 islarger than that of the first multi-axis lens 16. The number of the lensopenings of each of the first and second illumination multi-axiselectron lenses 510 and 512 may be the same as the number of thecathodes 12 included in the electron beam generator 10. Moreover, eachof the first and second illumination multi-axis electron lenses 510 and512 may further include at least one dummy lens opening through which noelectron beam passes during the exposure process.

The first illumination multi-axis electron lens 510 adjusts the focalpoint of the electron beams generated at the electron beam generator 10.More specifically, it is preferable that the first illuminationmulti-axis electron lens 510 adjusts the focal point of each of theelectron beams, so that each of the electron beams, which have passedthrough the first illumination multi-axis electron lens 510, form across over between the first and the second illumination multi-axiselectron lens 510 and 512. Then, the second illumination multi-axiselectron lens 512 performs a further focus adjustment for the electronbeam that has been subjected to the focus adjustment in the firstillumination multi-axis electron lens 510, so as to make the electronbeam incident on the first shaping member 14. In this case, it ispreferable that the second illumination multi-axis electron lens 512adjusts the focal points of the electron beams incident thereon in sucha manner that the electron beams after passing through the secondillumination multi-axis electron lens 512 are incident on the firstshaping member 14 substantially perpendicular thereto.

The electron beams after passing through the first and secondillumination multi-axis electron lenses 510 and 512 are incident on thefirst shaping member 14, in which the electron beams are divided. Therespective divided electron beams are independently converged of eachother by the first multi-axis electron lens 16. The electron beams arethen deflected by the first and second shaping deflecting units 18 and20, and are incident on the desired positions on the second shapingmember 22. The second shaping member 22 shapes the electron beams tohave desired cross-sectional shapes. In addition, the electron beamshaping unit may further include the slit cover 11 (shown in FIG. 1)between the electron beam generator 10 and the first shaping member 14.

As described above, the electron beam shaping unit 110 of this examplecan cast the electron beams generated by the electron beam generator 10onto the first shaping member 14 by means of the illumination multi-axiselectron lenses to divide the cast electron beams. Therefore, even in acase where the interval between the cathodes 12 of the electron beamgenerator 10 that is an electron gun array is relatively large, forexample, a number of electron beams can be generated efficiently. Also,since the interval between the cathodes 12 can be made larger, it ispossible to form the electron beam generator 10 easily.

FIG. 4 schematically shows an exemplary structure of the blankingelectrode array 26. The blanking electrode array 26 includes an aperturepart 160 having a plurality of apertures 166 that allow the electronbeams passing there-through, respectively, deflecting electrode pads 162and grounded electrode pads 164 that are to be used as connections withthe blanking electrode array controller 86 shown in FIG. 1. It isdesirable that the aperture part 160 is arranged at the center of theblanking electrode array 26. It is also preferable that the blankingelectrode array 26 has at least one dummy opening through which noelectron beam passes in an area surrounding the aperture part 160. Whenthe blanking electrode array 26 has the dummy opening, the inductance ofexhaustion can be reduced, thus allowing the pressure in the body 8 tobe lowered efficiently.

FIG. 5 shows a cross section of the blanking electrode array 26 shown inFIG. 4. The blanking electrode array 26 has the apertures 166 each ofwhich can allow the corresponding electron beam to pass there-through, adeflecting electrode 168 and a grounded electrode 170 provided for eachaperture that are used for deflecting the passing electron beam, and thedeflecting electrode pads 166 and the grounded electrode pads 164 to beused as the connection with the blanking electrode array controller 86(shown in FIG. 1), as shown in FIG. 5.

The deflecting electrode 168 and the grounded electrode 170 are providedfor each aperture 166. The deflecting electrode 168 is electricallyconnected to the deflecting electrode pad 162 via a wiring layer, whilethe grounded electrode 170 is electrically connected to the groundedelectrode pad 164 via a conductive layer. The blanking electrode arraycontroller 86 supplies control signals for controlling the blankingelectrode array 26 to the deflecting electrode pads 162 and the groundedelectrode pads 164 via connectors such as a probe card or a pogo pinarray.

Next, the operation of the blanking electrode array 26 is described.When the blanking electrode array controller 86 does not apply thevoltage to the deflecting electrode 168 of the aperture 166, no electricfield is generated between the deflecting electrode 168 and theassociated grounded electrode 170. Thus, the electron beam entering theaperture 166 passes through the aperture 166 with no substantial effectof the electric field. The electron beam that has passed through theaperture then passes through the corresponding opening of the electronbeam blocking member (shown in FIG. 1) so as to reach the wafer 44.

When the blanking electrode array controller 86 applies the voltage tothe deflecting electrode 168 of the aperture 166, an electric field isgenerated between the deflecting electrode 168 and the associatedgrounded electrode 170 based on the applied voltage. Thus, the electronbeam entering the aperture 166 is affected by the generated electricfield so as to be deflected. More specifically, the electron beam isdeflected in such a manner that the electron beam after passing throughthe aperture is incident on the outer area of the corresponding openingof the electron beam blocking member 28. Therefore, the deflectedelectron beam can pass through the aperture but cannot pass through thecorresponding opening of the electron beam blocking member 28, failingto reach the wafer 44. The blanking electrode array 26 and the electronbeam blocking member 28 operate in the above-mentioned manner, therebyit can be switched for each electron beam independently of otherelectron beams whether or not the electron beam is incident on the wafer44.

FIG. 6 schematically shows a structure of the first shaping deflectingunit 18 for deflecting the electron beams. It should be noted that thesecond shaping deflecting unit 20 and the deflecting unit 60 included inthe electron beam exposure apparatus 100 can have the same structure asthat of the first shaping deflecting unit 18. Thus, only the structureof the first shaping deflecting unit 18 is described below as a typicalexample.

The first shaping deflecting unit 18 includes a substrate 186, adeflector array 180 and deflecting electrode pads 182. The deflectorarray 180 is provided at the center of the substrate 186. The deflectingelectrode pads 182 are desirably arranged in peripheral areas of thesubstrate 186. It is preferable that the substrate 186 has at least onedummy opening (see FIG. 1) through which no electron beam passes in anarea surrounding the region where the deflector array 180 is provided.

The deflector array 180 has a plurality of deflectors 184, each of whichis formed by deflecting electrodes and an opening. The deflectingelectrode pads 182 are electrically connected to the shaping-deflectorcontroller 84 (shown in FIG. 1) via connectors such as a probe card or apogo pin array. Referring to FIG. 4, the deflectors 184 of the deflectorarray 180 are provided so as to correspond to the apertures of theblanking electrode array 26, respectively.

FIGS. 7A, 7B and 7C schematically show an exemplary arrangement of thedeflector 184. As shown in FIG. 7A, the deflector 184 includes anopening 194 through which an electron beam can pass, a plurality ofdeflecting electrodes 190 which can deflect the electron beam passthrough the opening 194, and wirings 192 for electrically connecting thedeflecting electrodes 190 to the deflecting electrode pads 182 (see FIG.6), respectively. The deflecting electrodes 190 are provided to surroundthe opening 194. The deflector 184 is preferably an electrostatic typedeflector that can deflect the electron beam at high speed by using anelectric field, and is more preferably a cylindrical eight-electrodetype having four pairs of electrodes in which the electrodes of eachpair are opposed to each other.

The operation of the deflector 184 is described. When a predeterminedvoltage is applied to each of the deflecting electrodes 190, an electricfield is generated in the opening 194. The electron beam incident on theopening 194 is affected by the generated electric field, so as to bedeflected in a predetermined direction corresponding to the orientationof the electric field by the amount corresponding to the electric-fieldintensity. Thus, the electron beam can be deflected to a desiredposition by applying the voltages to the respective deflectingelectrodes 190 so as to generate the electric field that can deflect theelectron beam in the desired direction by the desired amount.

As shown in FIG. 7B, the deflector 184 can correct astigmatism for theelectron beam passing through the opening 194 by applying apredetermined voltage to predetermined ones of the deflecting electrodes190 that are opposed to each other and applying different voltages toother deflecting electrodes 190. Moreover, as shown in FIG. 7C, thefocus correction can be performed for the electron beam passing throughthe opening 194 by applying substantially the same voltages to all thedeflecting electrodes 190.

FIG. 8 is a top view of the first multi-axis electron lens 16 that is anelectron lens according to an embodiment of the present invention.Please note that the second multi-axis electron lens 24, the thirdmulti-axis electron lens 34, the fourth multi-axis electron lens 36 andthe fifth multi-axis electron lens 62 all included in the electron beamexposure apparatus 100 have the same structure as that of the firstmulti-axis electron lens 16. Thus, the structure of the multi-axiselectron lens is described referring to the first multi-axis electronlens 16 as a typical example.

The first multi-axis electron lens 16 includes a lens part 202 having aplurality of lens openings 204 through which electron beams can pass,respectively, and a coil part 200 provided in an area surrounding thelens part 202 to generate a magnetic field. The lens part 202 includes alens region 206 where the lens openings 204 are provided. It ispreferable that the lens opening 204 is arranged to correspond to theposition of the associated aperture 166 of the blanking electrode array26 and the position of the associated deflector 184 of the deflectorarray 180, referring to FIGS. 4 and 6. It is further preferable thateach of the lens openings 204 is provided to have substantially the sameaxis as those of the corresponding openings of the electron beam shapingmembers, the deflecting units and the blanking electrode array 26.

It is desirable that the lens part 202 has at least one dummy opening205 through which no electron beam passes. The dummy opening 205 isdesirably arranged in the lens part 202 so as to make the lens intensityin each lens opening 204 substantially equal to the lens intensity inthe other lens opening 204. Such dummy openings 205 provided in the lenspart 202 enable the adjustment of the lens intensity so as to besubstantially equal in all the lens openings 204, i.e., to make themagnetic field intensity substantially uniform at all the lens openings204.

In this example, the dummy openings 205 are provided in the outer regionof the lens region 206. In this case, the lens openings 204 and thedummy openings 205 may be provided to form a lattice including the lensopenings 204 and the dummy openings 205 as lattice points. Moreover, thedummy openings 205 may be arranged to be circular in the outer peripheryof the lens region 206. In an alternative example, the dummy openings205 maybe arranged inside of the lens region 206 in the lens part 206.By adjusting the arrangement of the dummy openings 205, the lensintensity in each lens opening 204 can be more finely adjusted.

The lens part 202 may include the dummy opening 205 having differentsizes and/or shapes from those of the lens openings 204. In this case,the lens intensities in the lens openings 204 can be more finelyadjusted by adjusting the sizes and/or shapes of the dummy openings 205.

FIG. 9 is a top view of another exemplary first multi-axis electron lens16. The lens part 202 may include the dummy openings 205 arranged tomultiple plies. In this case, the lens openings 204 and the dummyopenings 205 may be arranged to form a lattice including the lensopenings 204 and the dummy openings 205 as lattice points. Moreover, thedummy openings 205 may be provided to form a circle in the outerperipheral region of the lens region 206. Furthermore, the lens part 202may include the dummy openings 205 in the outer peripheral region of thelens region 206, some of which are arranged to form a lattice while theremaining ones are arranged to be circular. The first multi-axiselectron lens 16 can perform further fine adjustment of the lensintensity in each lens opening 204 by including the dummy openings 205arranged to be multiple plies.

FIG. 10 shows another exemplary first multi-axis electron lens 16. Thelens part 202 may include a plurality of dummy openings 205 havingdifferent opening sizes in the outer peripheral region of the lensregion 206. For example, in a case where the magnetic field generated inthe lens opening 204 in the outer peripheral region of the lens region206 is stronger than that at the center thereof, it is preferable that aparticular lens opening 204 is formed to have a larger opening size thanthat of other lens openings 204 positioned on the inner side of thepredetermined lens opening 204. It is also preferable that the openingsizes of the lens openings 204 are substantially symmetrical withrespect to a center axis of the lens region 206 where the lens openings204 are provided.

The lens part 202 may include the dummy openings 205 having differentopening sizes to be multiple plies in the outer peripheral region of thelens region 206. In this case, the lens openings 204 and the dummyopenings 205 may be arranged to form a lattice. Also, the dummy openings205 may be formed to be circular in the outer peripheral region of thelens region 206. The first multi-axis electron lens 16 can performfurther fine adjustment of the lens intensity in each lens opening 204by including the dummy openings 205 having the different opening sizesarranged to be multiple plies.

FIG. 11 shows another exemplary first multi-axis electron lens 16. Asshown in FIG. 11, the lens part 202 may include the dummy lens openings205 arranged in such a manner that a distance between the dummy opening205 and the adjacent lens opening 204 is different from a distancebetween the lens openings 204. Also, the lens part 202 may include thedummy openings 205 arranged to be multiple plies at different intervalsthere-between. The first multi-axis electron lens 16 can perform furtherfine adjustment of the lens intensity in each lens opening 204 byincluding the dummy openings 205 having the appropriately adjusteddistances to the adjacent lens openings 204.

FIG. 12A shows an exemplary cross section of the first multi-axiselectron lens 16. Please note that the second multi-axis electron lens24, the third multi-axis electron lens 34, the fourth multi-axiselectron lens 36 and the fifth multi-axis electron lens 62 may have thesame structure as that of the first multi-axis electron lens 16. Thus,the structure of the multi-axis electron lens is described below basedon that of the first multi-axis electron lens 16 as a typical example.

As shown in FIG. 12A, the first multi-axis electron lens 16 includescoils 214, coil-magnetic conductive members 212 provided in areassurrounding the coils 214 and cooling units 215 provided between thecoils 214 and the coil-magnetic conductive members 212 that can cool thecoils 214. The lens part 202 includes a lens-magnetic conductive member210 that is a magnetic conductive member and a plurality of openingsprovided in the lens-magnetic conductive member 210. These openingsserve as the lens openings 204 allowing the electron beams to passthere-through.

In this example, the lens-conductive member 210 includes a firstlens-magnetic conductive member 210 a and a second lens-magneticconductive member 210 b, both of which have a plurality of openings. Itis preferable that the first lens-magnetic conductive member 210 a andthe second lens-magnetic conductive member 210 b are arranged to besubstantially parallel to each other with a non-magnetic conductivemember 208 interposed there-between. The openings provided in the firstand second lens-magnetic conductive members 210 a and 210 b form thelens openings 204. In other words, the magnetic field is generated inthe lens openings 204 by the first and second lens-magnetic conductivemembers 210 a and 210 b. The electron beams entering the lens openings204 are converged independently of each other by the effects of themagnetic field between the lens-magnetic conductive members 210 a and210 b without forming a crossover.

The coil magnetic conductive members 212 may be formed from magneticconductive material having a magnetic permeability different from thatof material for the first and second lens magnetic conductive members210 a and 210 b. It is desirable that the material for the coil magneticconductive member 212 has magnetic permeability higher than that of thematerial for the lens magnetic conductive members 210 a and 210 b. Forexample, the coil magnetic conductive members 212 are formed ofmalleable iron while the lens magnetic conductive members 210 are formedof Permalloy. By forming the coil magnetic conductive members from thematerial different from that for the lens magnetic conductive members,the intensities of the magnetic fields generated in the lens openings204 can be made uniform.

As shown in FIG. 12B, it is preferable that the lens part 202 has anon-magnetic conductive member 208 between the lens magnetic conductivemembers 210 in the areas other than the areas in which the lens openings204 are provided. The non-magnetic conductive member 208 may be providedto fill a space between the lens magnetic conductive members 210 in theareas other than the areas in which the lens openings 204 are provided.In this case, the non-magnetic member 208 has through holes that formthe lens openings 204 together with the openings of the lens magneticconductive members 210. The non-magnetic conductive member 208 has afunction of blocking the coulomb force generated between the adjacentelectron beams passing through the lens openings 204. The non-magneticconductive member 208 also serves as a spacer between the first lensmagnetic conductive member 210 a and the second lens magnetic conductivemember 210 b when the lens part 202 is formed.

FIG. 13 shows another exemplary multi-axis electron lens. A plurality ofmulti-axis electron lens may be integrated with each other to form asingle multi-axis electron lens. In this example, the multi-axiselectron lens includes the first and second magnetic conductive members210 a and 210 b, and further includes the third magnetic conductivemembers 210 c arranged to be substantially parallel to the first andsecond magnetic conductive members 210 a and 210 b, as shown in FIG. 13.Moreover, the coil part 200 includes a plurality of coils 200.

The openings provided in the respective magnetic conductive members 210a, 210 b and 210 c form the lens openings 204. The magnetic fields areformed between the first and second magnetic conductive members 210 aand 210 b and between the first and third magnetic conductive members210 a and 210 c. When the magnetic conductive members 210 b and 210 care arranged to be away from the conductive member 210 a by differentdistances, the different lens intensities can be obtained between therespective lens magnetic conductive members 210 a, 210 b and 210 c. Asdescribed above, the multi-axis electron lens of this example is formedby integrating a plurality of multi-axis electron lenses together. Thus,the size of the lens serving as a plurality of multi-axis electronlenses can be reduced. Also, this size reduction of the lens can reducethe size of the electron beam exposure apparatus 100.

FIGS. 14A and 14B show other examples of the lens part 200. At least oneof the lens magnetic conductive members 210 a and 210 b may include atleast one cut portion 216 formed in the outer periphery of each opening,as shown in FIG. 14A. In this case, it is preferable to form the cutportions 216 on a face of the first lens magnetic conductive member 210a and a face of the second lens magnetic conductive member 210 b thatare opposed to each other.

Moreover, the lens magnetic conductive members 210 a and 210 bpreferably include the cut portions 216 having different dimensions.More specifically, the depths of the cut portions 216 in a depthdirection of the lens magnetic conductive members 210 a and 210 b may bedifferent. Also, the sizes of the cut portions 216 may be changed tomake the sizes of the openings provided in the lens magnetic conductivemembers 210 a and 210 b different.

In a case where the intensity of the magnetic field generated in thelens opening 204 in the vicinity of the outer periphery of the lensmagnetic conductive members 210 is stronger than that at the center ofthe lens magnetic conductive members 210, for example, it is preferableto make the dimension of a certain cut portion 216 larger than that ofthe cut portion 216 arranged on the inner side of the certain cutportion 216. Moreover, it is preferable that the dimensions of the cutportions 216 are determined to be symmetrical with respect to the centeraxis of the lens region 206 that is a region of the lens magneticconductive members 210 in which the lens openings 204 are provided.

The lens magnetic conductive members 210 can adjust the intensities ofthe magnetic fields generated in the lens openings 204 by including thecut portions 216. Alternatively, as shown in FIG. 14B, the lens magneticconductive members 210 may include magnetic projections 218 havingelectro-conductivity provided between adjacent openings of the lensmagnetic conductive members 210 so as to project from surfaces of thelens magnetic conductive members 210 that are opposed to each other. Inthis case, the same effects obtained in the case of including the cutportions 216 can be obtained.

FIGS. 15A and 15B show another example of the lens part 202. As shown inFIG. 15A, the lens part 202 includes a plurality of first sub-magneticconductive members 240 a provided in areas surrounding the openings ofthe first lens magnetic conductive member 210 a and a plurality ofsecond sub-magnetic conductive members 240 b provided in areassurroundings the openings of the second lens magnetic conductive member210 b. The first sub-magnetic conductive members 240 a and the secondsub-magnetic conductive members 240 b are formed to project from therespective lens magnetic conductive members 210 a and 210 b,respectively, along the direction in which the electron beams areemitted.

It is preferable that the first and second sub-magnetic conductivemembers 240 a and 240 b are cylindrical in a plane substantiallyperpendicular to the direction in which the electron beams are emitted.In this example, the first sub-magnetic conductive members 240 a arearranged in the inner faces of the openings of the first lens magneticconductive members 210 a while the second sub-magnetic conductivemembers 240 b are arranged in the inner faces of the openings of thesecond lens magnetic conductive members 210 b. The openings formed bythe first sub-magnetic conductive members 240 a and the openings formedby the second sub-magnetic conductive members 240 b together form thelens openings 204 allowing the electron beams to pass there-through.

In the lens openings 204, magnetic fields are generated by the first andsecond sub-magnetic conductive members 240 a and 240 b. The electronbeams entering the lens openings 204 are converged independently of eachother by effects of the magnetic fields formed between the first andsecond sub-magnetic conductive members 240 a and 240 b.

A distance between a particular one of the first sub-magnetic conductivemembers 240 a and the second sub-magnetic conductive member 240 bopposed to the particular first sub-magnetic conductive member 240 a maybe different from the distance between another first sub-magneticconductive member 240 a and the corresponding second sub-magneticconductive member 240 b. In a case where the lens part 202 includes aplurality of pairs of the first and second sub-magnetic conductivemembers 240 a and 240 b, the distance between the first and secondsub-magnetic conductive members 240 a and 240 b in one pair beingdifferent from that in another pair, as shown in FIG. 15B, the intensityof the magnetic field 220 generated in each lens opening 204 can beadjusted. Thus, it is possible to make the intensities of the magneticfields in the respective lens openings 204 uniform. Moreover, the lensaxis formed in each lens opening 204 can be made substantially parallelto the direction in which the electron beams are emitted. Furthermore,the electron beams passing through the respective lens openings 204 canbe converged on substantially the same plane.

More specifically, in a case where the intensity of the magnetic fieldformed in the lens opening 204 in the vicinity of the outer periphery ofthe lens magnetic conductive member 210 is stronger than that at thecenter of the lens magnetic conductive member 210, for example, it ispreferable that the distance between the first and second sub-magneticconductive member 240 a and 240 b in a particular pair is larger thanthe distance between the first and second sub-magnetic conductivemembers 240 a and 240 b in the other pair farther from the coil 200 thanthe particular pair. Furthermore, it is preferable to determine thedistances between the first and second sub-magnetic conductive members240 a and 240 b to be symmetrical with respect to a center axis of aregion of the second magnetic conductive member 210 b where the openingsare provided.

FIGS. 16A, 16B and 16C show other examples of the lens part 202. Asshown in FIG. 16A, the lens part 202 may include fixing parts 242 thatare non-magnetic conductive members provided in areas surrounding thefirst sub-magnetic conductive members 240 a and the second sub-magneticconductive members 240 b arranged on substantially the same axes as thefirst sub-magnetic conductive members 240 a. By providing the fixingparts 242 in the surrounding areas of the first and second sub-magneticconductive members 240 a and 240 b, the concentricity of the first andsecond sub-magnetic conductive members 240 a and 240 b can be controlledwith high precision. Moreover, it is desirable to arrange the fixingparts 242 so as to be sandwiched between the first and secondsub-magnetic conductive members 240 a and 240 b while being in contactwith the first and second sub-magnetic conductive members 240 a and 240b. In this case, the distance between the first sub-magnetic conductivemember 240 a and the corresponding second sub-magnetic conductive member240 b can be controlled with high precision. Furthermore, the fixingpart 242 may be provided to be sandwiched between the first magneticconductive member 210 a and the corresponding second magnetic conductivemember 210 b while being in contact with the first and second magneticconductive members 210 a and 210 b. In this case, the fixing part 242can serve as a spacer for the first and second magnetic conductivemembers 210 a and 210 b.

As shown in FIG. 16B, a plurality of sub-magnetic conductive members 240may be provided on either one of the first and second lens magneticconductive members 210 a and 210 b. FIG. 16B shows a case where only thefirst lens magnetic conductive member 210 a includes the sub-magneticconductive members 240 as an example. In this case, the openingsprovided in the second lens magnetic conductive member 210 b and theopenings formed by the sub-magnetic conductive members 240 provided inthe first lens magnetic conductive member 210 a together form the lensopenings 204 allowing the electron beams passing there-through.Moreover, it is preferable that the openings provided in the second lensmagnetic conductive member 210 b have substantially the same sizes asthose of the openings formed by the sub-magnetic conductive members 240provided in the first lens magnetic conductive member 210 a. Please notethe above description is also applicable to a case where only the secondlens magnetic conductive member 210 b includes the sub-magneticconductive members 240.

In addition, the distances between the sub-magnetic conductive members240 and the corresponding second lens magnetic conductive members 210 bmay be varied, as shown in FIG. 16B. By varying the distances betweenthe sub-magnetic conductive members 240 and the second lens magneticconductive members 210 b, it is possible to adjust the intensities ofthe magnetic fields formed in the respective lens openings 204. Thus,the intensities of the magnetic fields of the lens openings 204 can bemade uniform. Moreover, the magnetic field formed in each lens opening204 can have a distribution substantially symmetrical with respect tothe center axis of the lens opening 204. Furthermore, the electron beamspassing through the respective lens openings 204 can be converged onsubstantially the same plane.

In a case where the intensity of the magnetic field formed in the lensopening 204 is stronger in the vicinity of the outer periphery of thelens magnetic conductive members 210 than that at the center thereof,for example, it is preferable to make the distance between a particularsub-magnetic conductive member 240 and the corresponding second lensmagnetic conductive member 210 b larger than the distance between thesub-magnetic conductive member 240 that is farther from the coil 200than the particular sub-magnetic conductive member 240 and thecorresponding second magnetic conductive member 210 b. Furthermore, itis preferable to determine the distances between the sub-magneticconductive members 240 and the second lens magnetic conductive members210 b respectively corresponding thereto so as to be substantiallysymmetrical with respect to the center axis of the region where the lensopenings 204 are provided.

As shown in FIG. 16C, the first sub-magnetic conductive members 240 amay be provided on a face of the first lens magnetic conductive member210 a that is opposed to the second lens magnetic conductive member 210b, while the second sub-magnetic conductive members 240 b are providedon a face of the second lens magnetic conductive member 210 b that isopposed to the first lens magnetic member 210 a. In this case, it ispreferable that each opening formed by the first and second sub-magneticconductive members 240 a and 240 b are substantially the same as thecorresponding openings in the first and second lens magnetic conductivemember 210 a and 210 b.

FIGS. 17A and 17B show an example of the lens-intensity adjuster thatcan adjust the lens intensity of the multi-axis electron lens. Thefirst, second, third and fourth lens-intensity controllers 17, 25, 35and 37 may have the same structure and functions. The firstlens-intensity adjuster 17 is described as a typical example in thefollowing description.

FIG. 17A is a cross-sectional view of the first lens-intensity adjuster17 and the lens part 202 included in the multi-axis electron lens. Thefirst lens-intensity adjuster 17 includes a substrate 530 arrangedsubstantially parallel to the multi-axis electron lens and adjustingelectrodes 532 provided on the substrate 530. The adjusting electrodes532 are an example of a lens-intensity adjuster for adjusting the lensintensity of the multi-axis electron lens.

The first lens-intensity adjuster 17 generates a desired electric fieldby applying a predetermined voltage to the adjusting electrode 532, sothat the speed of the electron beam that is to enter the lens opening204 can be increased or reduced. The electron beam entering the lensopening 204 after the speed thereof has been reduced requires a longertime period for passing through the lens opening 204, as compared to theelectron beam entering the lens opening 204 without being decelerated.In other words, the lens intensity applied by the magnetic field formedin the lens opening 204 to the electron beam incident thereon can beadjusted. Therefore, since the electron beam has been affected by themagnetic field formed in the lens opening 204 by the first and secondlens magnetic conductive members 210 a and 210 b for a longer timeperiod than the electron beam entering the lens opening 204 withoutbeing decelerated or the electron beam incident on the other lensopening 204, the position of the focal point of the electron beam andthe rotation of the exposed image of the electron beam can be adjusted.When the adjusting electrode 532 is provided for each lens opening 204,the adjustment of the position of the focal point, the adjustment of therotation of the exposed image or the like can be performed for eachelectron beam independently of other electron beams.

It is desirable to provide the adjusting electrodes 532 to beelectrically insulated from the lens magnetic conductive members 210 aand 210 b from the substrate 530 to the lens opening 204. In thisexample, the adjusting electrodes 532 are cylindrical electrodes each ofwhich is provided to surround the electron beam passing thorough thelens opening 204. In addition, in this example, the substrate 530 isarranged between the multi-axis electron lens and the electron beamgenerator 10 that generates the electron beams, so as to be opposed tothe second lens magnetic conductive member 210 b. The length of theadjusting electrode 532 in a direction along the direction in which theelectron beams are emitted is set to be longer than the inner diameterof the adjusting electrode 532. Also, the substrate 530 is provided toproject from the first lens magnetic conductive member 210 a that isdifferent from the second lens magnetic conductive member 210 b towardsthe direction in which the electron beams are emitted. In an alternativeexample, the substrate 530 may be provided between the multi-axiselectron lens and the wafer 44 to be opposed to the first lens magneticconductive member 210 a.

FIG. 17B is a top view of a surface of the first lens-intensity adjuster17 on which the adjusting electrodes 532 are provided. The firstlens-intensity adjuster 17 further includes an adjusting electrodecontroller 536 that can apply desired voltages to the adjustingelectrodes 532. It is desirable that the adjusting electrodes 532 areelectrically connected to the adjusting electrode controller 536 viawirings 538 provided on the substrate 530. Moreover, it is preferablethat the first lens-intensity adjuster 17 includes a plurality ofadjusting electrode controllers 536 for applying the adjustingelectrodes 532, respectively. The adjusting electrodes 532 may have amulti-electrode structure in which the electrodes can form an electricfield in a direction substantially perpendicular to the direction inwhich the electron beams are emitted. For example, the adjustingelectrode 532 has eight electrodes opposed to each other, as shown inFIG. 8A. In this case, it is preferable that the first lens-intensityadjuster 17 further includes a means operable to apply differentvoltages to the respective electrodes included in the multi-electrodestructure of the adjusting electrode 532. By applying the differentvoltages to the respective electrodes of the adjusting electrode 532,astigmatism correction and/or deflection of the electron beam can berealized. Furthermore, a shift of the focal point caused by thedeflected position and/or the cross-sectional size of the electron beamcan be corrected.

FIGS. 18A and 18B show another exemplary lens-intensity adjuster thatcan adjust the lens intensity of the multi-axis electron lens. FIG. 18Ais a cross-sectional view of the first lens-intensity adjuster 17 andthe lens part 202 of the multi-axis electron lens. The firstlens-intensity adjuster 17 includes a substrate 540 arrangedsubstantially parallel to the multi-axis electron lens and adjustingcoils 542 provided on the substrate 540 as an example of thelens-intensity adjuster for adjusting the lens intensity of themulti-axis electron lens. The first lens-intensity adjuster 17 generatesdesired electric fields by supplying predetermined currents to theadjusting electrodes 542, thereby making it possible to adjust theintensities of the magnetic fields formed in the lens openings 204 bythe first and second lens magnetic conductive members 210 a and 210 b.Thus, the lens intensity applied to the electron beam incident on thelens opening 204 by the magnetic field formed in that lens opening 204can be adjusted. Then, since the electron beam entering the lens opening204 is affected both by the magnetic field formed by the first andsecond lens magnetic conductive members 210 a and 210 b and the magneticfield formed by the adjusting coil 542, the focus position of theelectron beam and the rotation of the exposed image can be adjusted.Furthermore, the adjustment of the focus position and the adjustment ofthe rotation of the exposed image can be performed for the each of theelectron beams passing through the respective lens openings 204 byproviding the adjusting coil 542 in each of the lens openings 204.

It is desirable to arrange the adjusting coil 542 to be electricallyinsulated from the lens magnetic conductive members 210 a and 210 b fromthe substrate 540 to the lens opening 204. The adjusting coil 542 ofthis example is a solenoid coil provided to surround the electron beampassing through the corresponding lens opening 204. Moreover, in thisexample, the substrate 540 is provided between the multi-axis electronlens and the electron beam generator 10 so as to be opposed to thesecond lens magnetic conductive member 210 b and to project from thefirst lens magnetic conductive member 210 a differently from the secondlens magnetic conductive member 210 b toward the direction in which theelectron beams are radiated. In an alternative example, the adjustingcoil 542 maybe provided in the outside of the corresponding lens opening204 to surround the optical axis of the electron beam passing throughthe lens opening 204 so that the magnetic field formed in the lensopening 204 is affected by the adjusting coil 542. Furthermore, thefirst lens-intensity adjuster 17 may include a radiation member,provided in the vicinity of the adjusting coil 542 or in contact withthe adjusting coil 542, for inducing heat generated in the adjustingcoil 542. The radiation member may be a cylindrical non-magneticconductive member, for example. Also, the radiation member may bearranged in the surrounding area of the adjusting coil 542.

FIG. 18B is a top view of the surface of the first lens-intensityadjuster 17 on which the adjusting coils 542 are provided. The firstlens-intensity adjuster 17 further includes an adjusting coil controller546 for supplying desired currents to the respective adjusting coils542. It is desirable that the adjusting coils 542 are electricallyconnected to the adjusting coil controller 546 via wirings 548 providedon the substrate 540. Moreover, it is preferable that the firstlens-intensity adjuster 17 includes a plurality of adjusting coilcontrollers 546 each of which independently applies a voltage to acorresponding one of the adjusting coils 542.

FIGS. 19A and 19B show an exemplary arrangement of the firstshaping-deflecting unit 18 and the blocking unit 600. FIG. 19A is across-sectional view of the first shaping-deflecting unit 18 and theblocking unit 600, while FIG. 19B is a top view thereof. Although thefirst shaping-deflecting unit 18 is described as an example in thefollowing description, the second shaping-deflecting unit 20 and theblanking electrode array 26 can have the same arrangement as the firstshaping-deflecting unit 18.

The first shaping-deflecting unit 18 includes a substrate 186 providedto be substantially perpendicular to the direction in which the electronbeams are emitted, openings 194 provided in the substrate 186,deflectors 190 respectively provided in the openings 194 along thedirection in which the electron beams are emitted, as shown in FIG. 19A.The blocking unit 600 includes a first blocking substrate 602 and asecond blocking substrate 608 provided to be substantially perpendicularto the direction in which the electron beams are emitted, first blockingelectrodes 604 provided on the first blocking substrate 602 along thedirection in which the electron beams are emitted, and second blockingelectrodes 610 provided on the second blocking substrate 608 along thedirection in which the electron beams are emitted. The first and secondblocking substrate 602 and 608 are arranged to be opposed to each otherwith the substrate 186 of the first shaping-deflecting unit 18interposed there-between.

The first blocking electrodes 604 are preferably arranged between thedeflectors 190 so as to extend along the direction in which the electronbeams are emitted from a position closer to the electron beam generator10 (shown in FIG. 1) than the end of the deflector 190 that is closer tothe electron beam generator 10 to a position closer to the wafer 44(shown in FIG. 1) than the other end of the deflector 190. It is alsopreferable that the first blocking electrodes 604 are grounded.Moreover, the second blocking electrodes 610 are preferably arranged tobe opposed to the first blocking electrodes 604 with the substrate 186sandwiched there-between so as to extend along the direction in whichthe electron beams are emitted. Also, it is preferable to ground thesecond blocking electrodes 610. Furthermore, as shown in FIG. 19B, thefirst and second blocking electrodes 604 and 610 are preferably arrangedto form a lattice between the deflectors 190.

FIG. 20 shows an exemplary specific arrangement of the first and secondblocking electrodes 604 and 610. It is preferable that the first andsecond blocking electrodes 604 and 610 have a plurality of holes each ofwhich opens substantially perpendicular to the direction in which theelectron beams are emitted. It is more preferable that the first andsecond blocking electrodes 604 and 610 are meshes, as shown in FIG. 20.By providing the first and second blocking electrodes 604 and 610arranged in the body 8 with the holes, interference between each of theelectron beams and the electric fields generated for other electronbeams can be prevented without reducing the conductance of exhaustion ina case where the body 8 is exhausted to vacuum via the exhaustion holes708, thereby the electron beams can be made incident on the wafer 44with high precision.

FIGS. 21A and 21B show another example of the first shaping-deflectingunit 18 and the blocking unit 600. FIG. 21A is a cross-sectional view ofthe first shaping-deflecting unit 18 and the blocking unit 600 whileFIG. 21B is a view thereof seen from a wafer-side.

The blocking unit 600 includes the substrate 602 and a plurality ofblocking electrodes 606. As shown in FIGS. 21A and 21B, the blockingelectrodes 606 maybe arranged to be cylindrical in the are assurrounding the respective deflectors 190. It should be noted theblocking electrodes 606 can have any shape as long as the electric fieldgenerated by a particular first shaping-deflecting unit 18 can beblocked from the electric fields generated by the other firstshaping-deflecting units 18 so that the electric field generated by theparticular first shaping-deflecting unit 18 cannot affect the electronbeams other than the corresponding electron beam.

FIG. 22 shows another exemplary arrangement of the firstshaping-deflecting unit 18. As shown in FIG. 22, the firstshaping-deflecting unit 18 of this example includes a substrate 186provided to be substantially perpendicular to the direction in which theelectron beams are emitted, openings 194 provided in the substrate 186,deflectors 190 provided for the respective openings 194, first blockingelectrodes 604 provided between adjacent openings 194 and secondblocking electrodes 610 provided to be opposed to the first blockingelectrodes 604 with the substrate 186 sandwiched there-between so as toextend along a direction substantially perpendicular to the substrate186.

The deflectors 190 are arranged along the first direction substantiallyperpendicular to the substrate 186. The first blocking electrodes 604are preferably arranged along the first direction so as to extend longerthan the deflectors 190. The first and second blocking electrodes 604and 610 may be arranged to form a lattice between the openings 194.Moreover, the first and second blocking electrodes 604 and 610 may haveholes arranged in a direction substantially perpendicular to thesubstrate 186. In this case, it is preferable that the first and secondblocking electrodes 604 and 610 are meshes. Furthermore, the first andsecond blocking electrodes 604 and 610 are arranged at any position aslong as the first and second blocking electrodes 604 and 610 arearranged between the openings 194 on the lower surface and the uppersurface of the substrate 186, respectively.

FIGS. 23A and 23B show an exemplary arrangement of the deflecting unit60, the fifth multi-axis electron lens 62 and a blocking unit 900. Asshown in FIG. 23A, the deflecting unit 60 includes a substrate 186 and aplurality of deflectors 190 respectively provided in the lens openingsof the fifth multi-axis electron lens 62. The fifth multi-axis electronlens 62 includes the first magnetic conductive member 210 b having aplurality of first openings allowing electron beams passingthere-through and the second magnetic conductive member 210 a having aplurality of second openings allowing the electron beams that havepassed through the first openings to pass there-through. The first andsecond magnetic conductive members 210 b and 210 a are arranged to besubstantially parallel to each other. The blocking unit 900 includesfirst blocking electrodes 902 provided to extend in a direction from thefirst magnetic conductive member 210 b toward the electron beamgenerator 10, a first blocking substrate 904 provided to besubstantially parallel to the first magnetic conductive member 210 b forholding the first blocking electrodes 902, second blocking electrodes910 provided to extend in a direction from the second magneticconductive member 210 a toward the wafer 44, a second blocking substrate908 provided to be substantially parallel to the second magneticconductive member 210 a for holding the second blocking electrodes 910,and third blocking electrodes 906 provided between the first and secondmagnetic conductive members 210 b and 210 a, as shown in FIG. 23A.

The first, second and third blocking electrodes 902, 910 and 906 maybearranged to form a lattice between the lens openings. Also, the first,second and third blocking electrodes 902, 910 and 906 may be provided inthe surrounding are as of the lens openings. Moreover, the first, secondand third blocking electrodes 902, 910 and 906 may have holes arrangedin a direction substantially perpendicular to the substrate 186. In thiscase, it is preferable that the first, second and third blockingelectrodes 902, 910 and 906 are formed by meshes. In addition, theblocking unit 900 may include no first blocking substrate 904. In thiscase, the first blocking electrodes 902 can be held by the substrate186. Similarly, the blocking unit 900 may include no second blockingsubstrate 908. In this case, the second blocking electrodes 910 can beheld by the second magnetic conductive member 210 a. Furthermore, theblocking unit 900 may not include the second blocking electrode 910 in acase where the deflectors 190 do not project from the second magneticconductive member 210 a towards the wafer 44, as shown in FIG. 23B.

FIG. 24 shows the electric field blocked by the blocking unit 600 or900. In FIG. 24, the electric field generated by the deflectors 190 inthe first shaping-deflecting unit 18 as an example is shown. When theblocking electrodes are provided between the electrodes of the adjacentdeflectors 190, the effects of the electric field generated by aparticular deflector 190 on the electron beams other than thecorresponding electron beam to be deflected by the particular deflector190 can be greatly reduced.

As a specific example, a case is considered where a negative voltage isapplied to the deflecting electrode of the deflector 190 a in order todeflect the electron beam passing through the opening 194 a, a positivevoltage is applied to the deflecting electrode of the deflector 190 c inorder to deflect the electron beam passing through the opening 194 c andno voltage is applied to the deflecting electrode of the deflector 190 bin order to allow the electron beam to pass straight through the opening194 b. In this case, as shown in FIG. 24, the first and second blockingelectrodes 604 and 610 can block the electric fields generated by thedeflectors 190 a and 190 c so as to greatly reduce the effects of thedeflectors 190 a and 190 c on the electron beam passing through thedeflector 190 b. Therefore, a plurality of electron beams can be castonto the wafer 44 with high precision.

FIG. 25 shows an example of the first and second shaping members 14 and22. The first shaping member 14 has a plurality of illumination areas560 that are to be illuminated with electron beams generated by theelectron beam generator 10, respectively. The first shaping member 14includes a first shaping opening in each illumination area 560 so as toshape the electron beam incident thereon. It is preferable that thefirst shaping openings have rectangular shapes.

Similarly, the second shaping member 22 has a plurality of illuminationareas 560 to be illuminated with the electron beams after beingdeflected by the first and second shaping-deflecting units 18 and 20.The second shaping member 22 includes a second shaping opening in eachillumination area 560 so as to shape the electron beam incident thereon.It is preferable that the second shaping openings have rectangularshapes.

FIG. 26A shows another example of the illumination areas 560 in thesecond shaping member 22. As shown in FIG. 26A, the illumination area560 includes the second shaping opening 562 described referring to FIG.25 and a plurality of pattern-opening areas 564 where pattern openingshaving different shapes from the second shaping opening 562 areprovided. It is preferable that the pattern-opening area 564 has a sizethat is substantially the same as or less than the maximum size of theelectron beam shaped by the first shaping member 14. It is alsopreferable that the shape of the pattern-opening area 564 is the same asor similar to the cross-sectional shape of the electron beam shaped bythe first shaping member 14.

FIGS. 26B, 26C, 26D and 26E show exemplary pattern openings 566. Asshown in FIGS. 26B and 26C, it is preferable that the pattern openings566 are openings for exposing openings to be provided at a constantinterval or a constant period, such as contact holes for electricallyconnecting transistors to be formed on the wafer to wirings or throughholes for electrically connecting the wirings to each other. The patternopenings 566 may be openings for exposing a line and space patternprovided at a constant interval or a constant period, such as gateelectrodes of the transistors or the wirings, as shown in FIGS. 26D and26E.

When each of the electron beams shaped in the first shaping member 14 isincident entirely on the pattern-opening area 564 of the illuminationarea 560 corresponding to the electron beam, a pattern to be formed byelectron beams after passing through the pattern openings 566 includedin the pattern-opening area 564 is exposed at once.

FIG. 27 shows an exemplary arrangement of the controlling system 140described before referring to FIG. 1. The controlling system 140includes the general controller 130, the individual controller 120, themulti-axis electron lens controller 82 and the wafer-stage controller96. The general controller 130 includes a central processing unit 220for controlling the controlling system 140, an exposure pattern storingunit 224 for storing an exposure pattern to be exposed onto the wafer44, an exposure data generating unit 222 for generating exposure datathat is an exposure pattern in an area to be exposed by the electronbeams based on the exposure pattern stored in the exposure patternstoring unit 224, an exposure data memory 226 that is a memory for theexposure data, an exposure data sharing unit 228 for allowing theexposure data to be shared with other controllers, and a positioninformation calculating unit 230 for calculating the exposure data andposition information of the wafer stage 46.

The individual controller 120 includes the electron beam controller 80for controlling the electron beam generator 10, the shaping-deflectorcontroller 84 for controlling the shaping-deflecting units 18 and 20,the lens-intensity controller 88 for controlling the lens-intensityadjusters 17, 25, 35 and 37, the blanking electrode array controller 86for controlling the blanking electrode array 26, and the deflectorcontroller 98 for controlling deflecting unit 60. The multi-axiselectron lens controller 82 controls currents to be supplied to thecoils in the multi-axis electron lenses 16, 24, 34, 36 and 62 inaccordance with an instruction from the central processing unit 20.

The operation of the controlling system 140 in this example is describedbelow. Based on the exposure pattern stored in the exposure patternstoring unit 224, the exposure data generating unit 222 generates theexposure data and stores the generated exposure data in the exposuredata memory 226. The exposure data sharing unit 228 reads the exposuredata stored from the exposure data memory 226, stores it therein, andsupplies it to the position information calculating unit 230 and anindividual controller 120. The exposure data memory 226 is preferably abuffer memory for temporarily storing the exposure data. Morespecifically, it is preferable that the buffer memory as the exposuredata memory 226 stores the exposure data corresponding to an area to beexposed next. The individual electron beam controller 122 controls eachof the electron beams based on the received exposure data. The positioninformation calculating unit 230 supplies information used for adjustinga position to which the wafer stage 46 is to move to the wafer-stagecontroller 96 based on the received exposure data. The wafer-stagecontroller 96 then controls the wafer-stage driving unit 48 to move thewafer stage 46 to a predetermined position based on the information fromthe position information calculating unit 230 and an instruction fromthe central processing unit 220.

FIG. 28 shows details of the components included in the individualcontrolling system 120. The blanking electrode array controller 86includes individual blanking electrode controllers 126 each of whichgenerates a reference clock and controls, for a corresponding one of telectron beams, whether or not a voltage is applied to the deflectingelectrode 168 corresponding to the electron beam in accordance with thereference clock based on the received exposure data, and amplifyingparts 146 that amplify signals output from the individual blankingelectrode controllers 126 so as to output the amplified signals to theblanking electrode array 26.

The shaping-deflector controller 84 includes a plurality of individualshaping-deflector controllers 124 for outputting a plurality of units ofvoltage data indicating voltages to be applied to the deflectingelectrodes of the shaping-deflecting units 18 and 20, respectively,digital-analog converters (DAC) 134 for converting the voltage dataunits received from the individual shaping-deflector controllers 124 indigital data form into analog data so as to output the analog data, andamplifying parts 144 each amplifies the analog data received from thecorresponding DAC 134 to supply the amplified analog data to theshaping-deflecting unit 18 or 20.

The lens-intensity controller 88 includes individual lens-intensitycontrollers 125 for respectively outputting a plurality of data unitsused for controlling voltages to be applied to the lens-intensityadjusters 17, 25, 35 and 37 or currents to be supplied thereto, Daces135 each of which converts the data unit received from the correspondingindividual lens-intensity controller 124 into analog data, andamplifying parts 145 each of which amplifies the analog data receivedfrom the corresponding DAC 135 to supply the amplified analog data tothe shaping-deflecting unit 18 or 20.

The lens-intensity controller 88 controls the voltages to be applied tothe respective lens-intensity adjusters 17, 25, 35 and 37 and/or thecurrents to be supplied thereto so as to make the lens intensities inthe lens openings 204 in each of the multi-axis electron lensessubstantially uniform based on the instruction from the centralprocessing unit 220. In this example, the lens-intensity controller 88supplies a constant voltage and/or current to each of the lens-intensityadjuster 17, 25, 35 or 37 in the exposure process. In this case, thelens-intensity controller 88 controls each of the lens-intensityadjuster 17, 25, 35 or 37 based on data for calibrating the focus and/orrotation of each electron beam with respect to the wafer 44 obtainedprior to the exposure process. That is, the lens-intensity controller 88may control the respective lens-intensity adjusters 17, 25, 35 and 37 inthe exposure process without using the exposure data.

The deflector controller 98 includes individual deflector controllers128 for respectively outputting a plurality of units of voltage dataindicating voltages to be applied to the deflecting electrodes of thedeflecting unit 60, Daces 138 each of which converts one of the voltagedata units received as digital data from the corresponding individualdeflector controller 128 into analog data so as to output the analogdata, and AMPs 148 each of which amplifies the analog data received fromthe corresponding DAC 138 to supply the amplified analog data to thedeflecting unit 60. It is desirable that the deflector controller 98includes the individual deflector controller 122, the DAC 138 and theAMP 148 for each of the deflecting electrodes included in the deflectingunit 60.

The operations of the deflector controller 84, the blanking electrodearray controller 86, and the deflector controller 98 are described.First, the individual blanking electrode controllers 126 determine timesat which the voltages are applied to the respective deflectingelectrodes 168 of the blanking electrode array 26 based on the exposuredata and the reference clock. In this example, the individual blankingelectrode controllers 126 control each of the electron beams whether ornot the electron beam is cast onto the wafer 44 at a different time fromthe time of the other electron beams. In other words, each individualblanking electrode controller 126 generates the time at which theelectron beam is cast onto the wafer 44 independently of the time forthe other electron beam, and controls whether or not the correspondingelectron beam passing through the blanking electrode array 26 is to becast onto the wafer 44 at the generated time. It is preferable theindividual blanking electrode controller 126 determines a time periodfor which the wafer 44 is illuminated with the corresponding electronbeam based on the received exposure data and the reference clock.

In accordance with the times generated by the individual blankingelectrode controllers 126, the individual shaping-deflector controllers124 output voltages to be applied to the deflecting electrodes of theshaping-deflecting units 18 and 20 in order to shape the cross-sectionalshapes of the electron beams based on the received exposure data. Alsoin accordance with the times generated by the individual blankingelectrode controllers 126, the individual deflectors 128 output aplurality of voltage data units specifying voltages to be applied to thedeflecting electrodes of the deflecting unit 60 based on the receivedexposure data in order to control the electron beams to be positioned atpositions on the wafer 44 to be illuminated with the electron beams,respectively.

FIG. 29 shows an example of the backscattered electron detector 50. Thebackscattered electron detector 50 includes a substrate 702 having aplurality of openings 704 allowing a plurality of electron beams to passthere-through, respectively, and electron detectors 700 for detectingelectrons radiated from marked portions (not shown) provided on thewafer 44 or the wafer stage 46 so as to output a detection signal basedon the amount of the detected electrons. The electron detectors 700 ofthis example are provided between the openings 704 provided in thesubstrate 702. That is, the electron detectors 700 are arranged betweentwo electron beams passing through the adjacent two openings 704.

The electron detectors 700 are preferably arranged in such a manner thateach electron detector 700 is positioned on substantially the same lineas the optical axes of the two electron beams passing through the twoopenings 704 adjacent to the electron beam detector 700. Moreover, it isdesirable that the electron beam generator 10 generates three or moreelectron beams with a substantially constant interval while the electrondetectors 700 are provided between the three or more electron beamspassing through the three or more openings 704. Also, the openings 704are preferably arranged to form a lattice. In this case, it is desirablethat the electron beam detectors 700 are arranged between the openings704 of the lattice. Furthermore, the electron beam detector 700 may beprovided on the outer side of the openings 704 arranged at the outermostpositions.

FIG. 30 shows another exemplary arrangement of the backscatteredelectron detector 50. The backscattered electron detector 50 includes asubstrate 702 having a plurality of openings 704 allowing a plurality ofelectron beams to pass there-through, respectively, and electrondetectors 700 for detecting electrons radiated from a target mark (notshown) on the wafer 44 or the wafer stage 46 so as to output a detectionsignal based on the amount of the detected electrons. The electrondetectors 700 of this example are arranged in such a manner that two ormore of the electron detectors 700 are positioned between the adjacentopenings 704. In other words, two or more the electron detectors 700 arearranged between the two electron beams passing through the two openings704 so as to correspond to the two openings 704, respectively. Moreover,the electron detectors 700 are arranged in the surrounding area of eachof the openings 704.

It is preferable that the two or more electron detectors 700 areprovided on substantially the same line as the optical axes of the twoelectron beams passing through the two openings 704 adjacent to theseelectron detectors 700. Moreover, it is desirable that the electron beamgenerator 10 generates three or more electron beams at a substantiallyconstant interval. In this case, the electron detectors 700 aredesirably arranged in such a manner that two or more of the electrondetectors 700 are positioned between the three or more electron beamspassing through the three or more openings 704, respectively. Inaddition, the openings 704 are preferably arranged to form a latticebetween which the electron detectors 700 are arranged in such a mannerthat two or more electron detectors 700 are positioned between theadjacent openings 704. Furthermore, the electron detectors 700 may beprovided on the outer side of the outermost openings 704.

FIG. 31 shows another exemplary backscattered electron detector 50. Thebackscattered electron detector 50 includes a substrate 702 having aplurality of openings 704 allowing a plurality of electron beams to passthere-through, respectively, electron detectors 700 for detecting theelectrons radiated from the target mark (not shown) provided on thewafer 44 or the wafer stage 46 to output a detection signal based on theamount of the detected electrons, and blocking plates 706 providedbetween the openings 704. The electron detectors 700 of this example arearranged in such a manner that two or more electron detectors 700 arepositioned between the adjacent openings 704 so as to respectivelycorrespond the openings 704.

It is preferable that the electron detectors 700 are further provided inareas surrounding each of the openings 704 provided on the substrate702. Moreover, the blocking plates 706 are preferably provided between aparticular electron beam and the electron beams adjacent to theparticular electron beam. That is, the blocking plates 706 are providedbetween the electron detectors provided in the surrounding area of aparticular opening 704 and the electron detectors provided in thesurrounding area of the opening 704 adjacent to the particular opening704.

The blocking plates 706 are arranged at any portions as long as eachblocking plate 706 is positioned between the electron beam and theelectron detector 700 that is corresponding thereto. It is preferablethat the blocking plate 706 is provided between the illuminationposition of the electron beam in a surface onto which the wafer is to beplaced and the electron detector provided in the second electron beam.It is also desirable that the blocking plates 706 are formed fromnon-magnetic conductive material. Moreover, it is desirable that theblocking plates 706 are grounded by being electrically connected to thesubstrate 702.

FIG. 32 shows still another exemplary arrangement of the backscatteredelectron detector 50. The blocking plates 708 may be arranged to form alattice between the electron detectors 700 provided in the surroundingareas of the openings 704 that are also arranged to form a lattice. Theblocking plates 708 may have any shapes as long as each blocking plate708 blocks a predetermined electron detector 700 from other electrondetectors 700 so as to avoid the radiation of the electrons from apredetermined target mark (not shown) to electron detectors other than apredetermined electron detector that corresponds to the predeterminedmarked portion.

FIG. 33 shows an electron beam exposure apparatus 100 according toanother embodiment of the present invention. In the present embodiment,each electron beam is provided to be away from electron beams adjacentthereto by narrower distances. The distance between the adjacentelectron beams may be set to be such a distance that all the electronbeams are incident on an area corresponding to one chip to be providedon the wafer, for example. The components labeled with the samereference numerals in FIG. 33 as those in FIG. 1 may have the samestructures and functions as the components of the electron beam exposureapparatus shown in FIG. 1. In the following description, structures,operations and functions of the electron beam exposure apparatus of thepresent embodiment that are different from those of the electron beamexposure apparatus shown in FIG. 1 are described.

The electron beam shaping unit includes an electron beam generator 10which can generate a plurality of electron beams, an anode 13 whichallows the generated electron beams to be radiated, a slit cover 11having a plurality of openings for shaping the cross-sectional shapes ofthe electron beams by allowing the electron beams to pass there-through,respectively, a first shaping member 14, a second shaping member 22, afirst multi-axis electron lens 16 which can converge the electron beamsindependently of each other to adjust focal points of the electronbeams, a slit-deflecting unit 15 that can deflect the electron beamsafter passing through the anode 13 independently of each other, andfirst and second shaping-deflecting units 18 and 20 which can deflectthe electron beams after passing through the first shaping member 14.

It is desirable that the slit cover 11 and the first and the secondshaping members 14 and 22 have grounded metal films such as platinumfilms, on surfaces thereof onto which the electron beams are incident.It is also desirable that each of the slit cover 11 and the first andsecond shaping members 14 and 22 includes a cooling unit for suppressingthe increase in the temperature caused by the incident electron beams.

The openings included in each of the slit cover 11 and the first andsecond shaping members 14 and 22 may have cross-sectional shapes each ofwhich becomes wider along the radiated direction of the electron beamsin order to allow the electron beams to pass efficiently. Moreover, theopenings of each of the slit cover 11 and the first and second shapingmembers 14 and 22 are preferably formed to be rectangular.

The illumination switching unit includes: a second multi-axis electronlens 24 which can converge a plurality of electron beams independentlyof each other to adjust focal points thereof; a blanking electrode array26 which switches for each of the electron beams whether or not theelectron beam is to be incident on the wafer 44; and an electron beamblocking member 28 that has a plurality of openings allowing theelectron beams to pass there-through, respectively, and can block theelectron beams deflected by the blanking electrode array 26. Theopenings of the electron beam blocking member 28 may havecross-sectional shapes each of which becomes wider along the radiateddirection of the electron beams in order to allow the electron beams toefficiently pass there-through.

The wafer projection system includes: a third multi-axis electron lens34 which can converge a plurality of electron beams independently ofeach other and adjust the rotations of the electron beams to be incidentonto the wafer 44; a fourth multi-axis electron lens 36 which canconverge a plurality of electron beams independently of each other andadjust the reduction ratio of each electron beam to be incident onto thewafer 44; a sub-deflecting unit 38 that is an independent deflectingunit for deflecting a plurality of electron beams independently of eachother towards desired positions on the wafer 44; a coaxial lens 52 whichcan function as an objective lens and has a first coil 40 and a secondcoil 54 for converging a plurality of electron beams independently ofeach other; and a main deflecting unit 42 that is a common deflectingunit for deflecting a plurality of electron beams towards substantiallythe same direction by desired amounts. The sub-deflecting unit 38 may beprovided between the first coil 54 and the second coil 40.

The main deflecting unit 42 is preferably an electrostatic typedeflector that can deflect a plurality of electron beams at high speedby using an electric field. More preferably, the main deflecting unit 42has a cylindrical eight-electrode structure having four pairs ofelectrodes in which the electrodes of each pair are opposed to eachother, or a structure including eight or more electrodes. Moreover, itis preferable that the coaxial lens 52 is provided to be closer to thewafer 44 than the multi-axis electron lens. In addition, although thethird multi-axis electron lens 34 and the fourth multi-axis electronlens 36 are integrated with each other in this example, these lenses maybe formed separately in an alternative example.

The controlling system 140 includes a general controller 130, amulti-axis electron lens controller 82, a coaxial lens controller 90, amain deflector controller 94, a backscattered electron processing unit99, a wafer-stage controller 96 and an individual controller 120 whichcan control exposure parameters for each of the electron beams. Thegeneral controller 130 is, for example, a work station and can controlthe respective controllers included in the individual controller 120.The multi-axis electron lens controller 82 controls currents to berespectively supplied to the first multi-axis electron lens 16, thesecond multi-axis electron lens 24, the third multi-axis electron lens34 and the fourth multi-axis electron lens 36. The coaxial electron lenscontroller 90 controls the number of currents to be supplied to thefirst and second coils 40 and 54 of the coaxial lens 52. The maindeflector controller 94 controls a voltage to be applied to the maindeflector 42. The backscattered electron processing unit 99 receives asignal based on the amount of backscattered electrons or secondaryelectrons detected in a backscattered electron detector 50 and notifythe general controller 130 that the backscattered electron processingunit 99 received the signal. The wafer-stage controller 96 controls thewafer-stage driving unit 48 so as to move the wafer stage 46 to apredetermined position.

The individual controller 120 includes an electron beam controller 80for controlling the electron beam generator 10, a shaping-deflectorcontroller 84 for controlling the first and second shaping-deflectingunits 18 and 20, a blanking electrode array controller 86 forcontrolling voltages to be applied to deflection electrodes included inthe blanking electrode array 26, and a sub-deflector controller 98 forcontrolling voltages to be applied to electrodes included in thedeflectors of the sub-deflecting unit 38.

Next, the operation of the electron beam exposure apparatus 100 in thepresent embodiment is described. First, the electron beam generator 10generates a plurality of electron beams. The generated electron beamspass through the anode 13 to enter the slit-deflecting unit 15. Theslit-deflecting unit 15 adjusts the incident positions on the slit cover11 onto which the electron beams after passing through the anode 13 areincident.

The slit cover 11 can block a part of each electron beam so as to reducethe area of the electron beam to be incident on the first shaping member14, thereby shaping the cross section of the electron beam to have apredetermined size. The thus shaped electron beams are then incident onthe first shaping member 14 that further shapes the electron beams. Eachof the electron beams after passing through the first shaping member 14has a rectangular cross section in accordance with a corresponding oneof the openings included in the first shaping member 14. The electronbeams after passing through the first shaping member 14 are converged bythe first multi-axis electron lens 16 independently of each other, sothat for each of the electron beams the focus adjustment of the electronbeam with respect to the second shaping member 22 is performed.

The first shaping-deflecting unit 18 deflects each of the electron beamshaving the rectangular cross sections independently of the otherelectron beams in order to make the electron beams incident on desiredpositions on the second shaping member 22. The second shaping-deflectingunit 20 further deflects the thus deflected electron beams independentlyof each other towards a direction approximately perpendicular to thesecond shaping member 22, thereby performing such an adjustment that theelectron beams are incident on the desired positions of the secondshaping member 22 approximately perpendicular to the second shapingmember 22. The second shaping member 22 having a plurality ofrectangular openings further shapes the electron beams incident thereonin such a manner that the electron beams have desired rectangular crosssections, respectively, when being incident on the wafer 44.

The second multi-axis electron lens 24 converges a plurality of electronbeams independently of each other to perform the focus adjustment of theelectron beam with respect to the blanking electrode array 26 for eachelectron beam. The electron beams that have been subjected to the focusadjustment by the second multi-axis electron lens 24 pass through aplurality of apertures of the blanking electrode array 26.

The blanking electrode array controller 86 controls whether or notvoltages are applied to deflection electrodes provided in the vicinityof the respective apertures of the blanking electrode array 26. Based onthe voltages applied to the deflection electrodes, the blankingelectrode array 26 switches for each of the electron beams whether ornot the electron beam is made incident on the wafer 44. When the voltageis applied, the electron beam passing through the corresponding apertureis deflected. Thus, the electron beam cannot pass through acorresponding opening of the electron beam blocking member 28, so thatit cannot be incident on the wafer 44. When the voltage is not applied,the electron beam passing through the corresponding aperture is notdeflected, so that it can pass through the corresponding opening of theelectron beam blocking member 28. Thus, the electron beam can beincident on the wafer 44.

The third multi-axis electron lens 34 adjusts the rotation of the imageof the electron beam to be incident on the wafer 44, which has not beendeflected by the blanking electrode array 26. The fourth multi-axiselectron lens 36 reduces the illumination diameter of each of theelectron beams incident thereon. Among the electron beams that havepassed through the third multi-axis electron lens 34 and the fourthmulti-axis electron lens 36, only the electron beam to be incident ontothe wafer 44 passes through the electron beam blocking member 28 so asto enter the sub-deflecting unit 38.

The sub-deflector controller 98 controls a plurality of deflectorsincluded in the sub-deflecting unit 38 independently of each other. Thesub-deflecting unit 38 deflects the electron beams incident on thedeflectors independently of each other in such a manner that thedeflected electron beams are incident on the desired positions on thewafer 44. The electron beams that have passed through the sub-deflectingunit 38 are subjected to the focus adjustment with respect to the wafer44 by the coaxial lens 52 having the first and second coils 40 and 54,so as to be incident on the wafer 44.

During the exposure process, the wafer-stage controller 96 moves thewafer stage 48 in predetermined directions. The blanking electrode arraycontroller 86 determines the apertures that allow the electron beams topass and performs an electric-power control for the respective aperturesbased on exposure pattern data. By changing the apertures allowing theelectron beams to pass there-through in accordance with the movement ofthe wafer 44 and then further deflecting the electron beams by the maindeflecting unit 42 and the sub-deflecting unit 38, a desired circuitpattern can be transferred by exposing the wafer 44. The method forilluminating the wafer with the electron beams is described laterreferring to FIGS. 37, 38A and 38B.

The electron beam exposure apparatus 100 of the present embodimentconverges a plurality of electron beams independently of each other.Thus, although a cross over is formed for each electron beam, all theelectron beams as a whole do not have its cross over. Therefore, even ina case where the current density of each electron beam is increased, theelectron beam error that may cause a shift of the focus or position ofthe electron beam due to coulomb interaction can be greatly reduced.

FIGS. 34A and 34B show an exemplary arrangement of the electron beamgenerator 10 shown in FIG. 33. FIG. 34A is a cross-sectional view of theelectron beam generator 10. In this example, the electron beam generator10 includes an insulator 106, cathodes 12 formed from material that canradiate thermoelectrons, such as tungsten or lanthanum hexaborane, grids102 formed to surround the cathodes 12, respectively, a cathode wiring500 for supplying currents to the cathodes 12, grid wirings 502 forapplying voltages to the grids 102, and an insulation layer 504. In thisexample, the electron beam generator 10 forms an electron gun array byincluding a plurality of electron guns 104 on the insulator 106 at aconstant interval.

It is preferable that the electron beam generator 10 includes a basepower source (not shown), having an output voltage of about 50 kV, forexample, that is commonly provided to the cathodes 12. The cathodes 12are electrically connected to the base power source via the cathodewiring 500. The cathode wiring 500 is preferably formed of refractorymetal, such as tungsten. In an alternative example, the electron beamgenerator 10 may include a base power source provided for each of thecathodes 12. In this case, the cathode wiring 500 is formed so as toelectrically connect each cathode 12 to a corresponding base powersource.

In this example, the electron beam generator 10 includes an individualpower source (not shown) having an output voltage of about 200 V, forexample, for each of the grid units, each including a plurality of grids102. Each grid 102 is connected to the corresponding individual powersource via the grid wiring 502. It is preferable that the grid wiring502 is formed of refractory metal, such as tungsten. It is alsodesirable that the grids 102 and the grid wirings 502 are electricallyinsulated from the cathodes 12 and the cathode wiring 500 by theinsulation layer 504. In this example, the insulation layer 504 isformed of insulating heat-resistant ceramics, such as aluminum oxide.

FIG. 34B is a view of the electron beam generator 10 seen from the wafer44 (shown in FIG. 33). In the present example, the electron beamgenerator 10 forms an electron gun array by arranging a plurality ofelectron guns 104 at a predetermined interval on the insulator 106. Itis preferable that the grid wirings 502 are formed on the insulationlayer 504 so as to suppress the insulation layer 504 from being charged.More specifically, the grid wiring 502 is preferably formed on astraight line connecting the corresponding grid 102 and the insulationlayer 504. The grid wirings 502 may be arranged so as not to cause ashort-circuit between adjacent grid wirings 502, and preferably arearranged in such a manner that the adjacent grid wirings 502 are asclose as possible without causing the short-circuit there-between.

In the present example, the electron beam generator 10 heats thecathodes 12 by supplying the currents to the cathodes 12 so as togenerate thermoelectrons. A heating member, such as a carbon member, maybe provided between the cathode 12 and the cathode wiring 500. Byfurther applying a negative voltage of 50 kV to the cathode 12, apotential difference is generated between the cathode 12 and the anode13 (shown in FIG. 33). The generated thermoelectrons are drawn from theelectron guns by using the thus generated potential difference, therebythe electron beam is obtained by accelerating the thermoelectrons.

Then, the obtained electron beam is stabilized by applying a negativevoltage of several hundred volts with respect to the potential of thecathode 12 to the grid 102 so as to adjust the amount of thethermoelectrons radiated toward the anode 13. It is preferable that theelectron beam generator 10 adjusts the electron beam amount for each ofthe electron beams by applying the voltages to the grids 102independently of each other by means of the individual power sources soas to adjust the amount of the thermoelectrons radiated towards theanode 13. In an alternative example, the slit cover 11 (shown in FIG.33) may be used as the anode.

Alternatively, the electron beam generator 10 may include a fieldemission device to generate the electron beams. Moreover, it ispreferable that the electron beam generator 10 always generates theelectron beams for a period of the exposure process, since it takes apredetermined time for the electron beam generator 10 to generate theelectron beams that are stabilized.

FIGS. 35A and 35B show an exemplary arrangement of the blankingelectrode array 26 shown in FIG. 33. FIG. 35A is an entire view of theblanking electrode array 26. The blanking electrode array 26 includes anaperture part 160 having a plurality of apertures through which theelectron beams pass, and deflecting electrode pads 162 and groundedelectrode pads 164 both of which are used as connectors with theblanking electrode array controller 86 shown in FIG. 33. It is desirablethat the aperture part 160 is arranged at the center of the blankingelectrode array 26. To the deflecting electrode pads 162 and thegrounded electrode pads 164, electric signals are supplied from theblanking electrode array controller 86 via a probe card or a pogo pinarray.

FIG. 35B is a top view of the aperture part 160. In FIG. 35B, thehorizontal direction of the aperture part 160 is represented with anx-axis while the vertical direction thereof is represented with ay-axis. The x-axis corresponds to a direction in which the wafer stage46 (shown in FIG. 33) moves the wafer 44 in a graded manner during theexposure process, while the y-axis corresponds to a direction in whichthe wafer stage 46 moves the wafer 44 continuously. More specifically,with respect to the wafer stage 46, the y-axis corresponds to adirection in which the wafer 44 is scanned to be exposed while thex-axis corresponds to a direction in which the wafer 44 is moved in agraded manner for exposing an area of the wafer 44 that has not beenexposed after the scanning exposure has been completed.

The aperture part 160 includes the apertures 166. The apertures 166 arearranged so as to allow all scanned areas to be exposed. In the exampleshown in FIG. 35B, the apertures are formed so as to cover the entirearea between the apertures 166 a and 166 b positioned at both ends ofthe x-axis. The apertures 166 adjacent to each other in the x-axisdirection are preferably arranged at a constant interval. In this case,referring to FIG. 33, it is preferable to determine the interval betweenthe adjacent apertures 166 to be equal to or less than the maximumdeflection amount by which the main deflecting unit 42 deflects theelectron beam.

FIGS. 36A and 36B shows an exemplary arrangement of the firstshaping-deflecting unit 18. FIG. 36A is an entire view of the firstshaping-deflecting unit 18. Please note that the secondshaping-deflecting unit 20 and the sub-deflecting unit 38 have the samestructure as that of the first shaping-deflecting unit 18. Thus, in thefollowing description, the structure of the deflecting unit is describedbased on the structure of the first shaping-deflecting unit 18 as atypical example.

The first shaping-deflecting unit 18 includes a substrate 186, adeflector array 180 and deflecting electrode pads 182 provided on thesubstrate 186. The deflector array 180 is provided at the center of thesubstrate 186, while the deflecting electrode pads 182 are provided inthe peripheral region of the substrate 186. The deflector array 180includes a plurality of deflectors each formed by a plurality ofdeflecting electrodes and an opening. The deflecting electrode pads 182are electrically connected to the shaping-deflector controller 84 bybeing connected to a probe card, for example.

FIG. 36B shows the deflector array 180. The deflector array 180 includesthe deflectors 184 for deflecting the electron beams, respectively. InFIG. 36B, the horizontal direction of the deflector array 180 isrepresented with an x-axis. The vertical direction thereof isrepresented with a y-axis. The x-axis corresponds to a direction inwhich the wafer stage 46 moves the wafer 44 in a graded manner duringthe exposure process, while the y-axis corresponds to a direction inwhich the wafer stage 46 moves the wafer 44 continuously during theexposure process. More specifically, with respect to the wafer stage 46,the y-axis is a direction in which the wafer 44 is scanned to beexposed, while the x-axis is a direction in which the wafer 44 is movedin a graded manner after the scanning exposure has been completed, inorder to expose an area of the wafer 44 that has not been exposed.

It is preferable that the deflectors 184 adjacent to each other in thex-axis direction are arranged at a constant interval. In this case,referring to FIG. 33, it is preferable to determine the interval betweenthe deflectors 184 to be equal to or less than the maximum deflectionamount by which the main deflecting unit 42 deflects the electron beam.With reference to FIG. 35B, the deflectors 184 of the deflector array180 are provided to correspond to the apertures of the blankingelectrode array 26, respectively.

In conventional techniques, the coaxial lens has been used in order toreduce the beam size. The size-reducing coaxial lens reduces thediameter of the electron beam incident thereon and also converges aplurality of electron beams so as to reduce the interval between theelectron beams. Thus, in accordance with the conventional techniques,especially, the interval between the adjacent electron beams reachingthe sub-deflecting unit 38 is very small, and therefore it is hard toform the deflector 184 for each of the electron beams.

According to the present invention, the multi-axis electron lens isused. Thus, after the electron beams have passed through the multi-axiselectron lens for reducing the electron beams, the interval between theadjacent electron beams is not reduced although the diameter of each ofthe electron beams is reduced. That is, the interval between theadjacent electron beams is sufficient even after the electron beams arereduced, it is possible to easily arrange the deflectors 184 havingdeflection abilities that can deflect the electron beams by desiredamounts at positions in the deflector array 180 that provide asatisfactory deflection efficiency.

FIG. 37 is a drawing for explaining the exposure operation for the wafer44 on the electron beam exposure apparatus 100 according to the presentembodiment. First, the operation of the wafer stage 46 during theexposure process is described. In FIG. 37, the horizontal direction ofthe wafer 44 is represented with an x-axis while the vertical directionthereof is represented with a y-axis. An exposure width Al is a widththat can be exposed without moving the wafer stage 46 in the x-axisdirection, and corresponds to an interval of the apertures 166 of theblanking electrode array 26 that are adjacent to each other in thex-axis direction, referring to FIG. 35. With reference to FIG. 33, theshaping-deflector controller 84 controls the shape of the electron beamto be incident, while the blanking electrode array controller 86controls whether or not the electron beam is to be incident onto thewafer 44. Then, the wafer-stage controller 92 moves the wafer stage 46in the y-axis direction, while the main deflector controller 94 and thesub-deflector controller 92 control the positions of the wafer 44 to beilluminated with the electron beams, thereby a first exposure area 400having the exposure width Al can be exposed. After the first exposurearea 400 has been exposed, the wafer stage 46 is moved in thex-direction by the amount corresponding to the exposure width A1 andthen starts to be moved in a direction opposite to the direction inwhich the wafer stage 46 is moved for exposing the first exposure area400, so that a second exposure area 402 can be exposed. By repeating theabove-mentioned exposure operation for the entire surface of the wafer44, a desired exposure pattern can be exposed onto the entire surface ofthe wafer 44. In the example shown in FIG. 37, a single scan performsthe exposure from one end to another end of the wafer 44. Alternatively,only a part of the surface of the wafer 44 may be exposed by the singlescan.

FIGS. 38A and 38B schematically show deflection operations of the maindeflecting unit 42 and the sub-deflecting unit 38 in the exposureprocess. FIG. 38A shows a main deflection area 410 of the wafer 44 is tobe exposed mainly by the deflection operation of the main deflectingunit 42. One side A2 of the main deflection area 410 corresponds to theamount by which the main deflecting unit 42 deflects the electron beamduring the exposure process. It is preferable that the main deflectionareas 410 adjacent to each other in the x-direction are arranged to bein contact with each other. However, the main deflection areas 410 maybe arranged in such a manner that at least one of the main deflectionareas 410 overlaps the other main deflection area 410 in thex-direction.

FIG. 38B schematically shows an exposing operation for exposing thedeflection area 410 by the electron beams. One side A3 of asub-deflection area 412 of the wafer 44 which is exposed by thedeflection operation of the sub-deflecting unit 38 corresponds to theamount by which the sub-deflecting unit 38 can deflect the electronbeams during the exposure process. In the present example, the maindeflection area 410 is eight times as large as the sub-deflection area412.

The sub-deflection area 412 a is exposed by the deflection operation ofthe sub-deflecting unit 38 to have a desired exposure pattern. After theexposure for the sub-deflecting area 412 has been completed, the maindeflecting unit 42 moves the electron beams to the sub-deflection area412 b. The sub-deflection area 412 b is then exposed by the deflectionoperation of the sub-deflecting unit 38 to have a desired exposurepattern. Similarly, the deflection operations of the main deflectingunit 42 and the sub-deflecting unit 38 are repeated along an arrow inFIG. 38B so as to expose desired exposure patterns, thereby the exposurefor the main deflection area 410 is completed.

FIG. 39 shows an example of the first multi-axis electron lens 16.Please note that the second, third and fourth multi-axis electron lenses24, 34 and 36 have the same structure as that of the first multi-axiselectron lens 16. Therefore, the structure of the multi-axis electronlens is described based on the first multi-axis electron lens 16 as atypical example in the following description.

The first multi-axis electron lens 16 includes a coil part 200 forgenerating a magnetic field and a lens part 202. The lens part 202includes lens openings 204 allowing the electron beams to passthere-through, respectively, and a lens region 206 where the lensopenings 204 are provided. The y-axis of the lens region 206 correspondsto the scanning direction of the wafer stage 46 (shown in FIG. 33),while the x-axis thereof corresponds to the direction in which the waferstage 46 is moved in a graded manner.

The lens openings 204 are arranged in such a manner that x-coordinatesof centers of the respective lens openings 204 have a constant interval,and preferably have an interval corresponding to the amount by which themain deflecting unit 42 deflects the electron beam when the wafer 44 isexposed by the electron beam, referring to FIG. 33. More specifically,it is preferable that the lens openings 204 are arranged to correspondto the apertures 166 of the blanking electrode array 26 and thepositions of the deflectors 184 included in the deflector array 180,respectively, referring to FIGS. 35A to 36B. Moreover, the lens part 202preferably includes at least one dummy opening 205 described withreference to FIGS. 8-11.

FIGS. 40A and 40B show examples of the cross section of the firstmulti-axis electron lens 16. As shown in FIG. 40A, the lens part 202 mayinclude non-magnetic conductive members 208 to interpose lens magneticconductive members 210. Moreover, the lens magnetic conductive members210 may be made thicker, as shown in FIG. 40B. In this case, coulombforce generated between the adjacent electron beams can be blocked morestrongly. In this example, the lens magnetic conductive member 210 maybemade thicker in such a manner that the surfaces of the lens part 202 arepositioned on substantially the same place as that the surfaces of thecoil part 200, as shown in FIG. 40B. Alternatively, the lens magneticconductive member 210 may be formed to be thicker so that the lens part202 is thicker than the coil part 200.

FIG. 41 shows an electron beam exposure apparatus 100 according toanother embodiment of the present invention. The electron beam apparatus100 includes a blanking aperture array (BAA) device 27 in place of theblanking electrode array 26 included in the electron beam exposureapparatus shown in FIG. 1. Moreover, the electron beam exposureapparatus 100 of the present embodiment includes electron lenses anddeflecting units having the same functions and operations as those ofthe electron lenses and deflecting units provided in the electron beamexposure apparatus shown in FIG. 33, thereby illuminating the wafer withthe electron beams divided by the BAA device 27 (that are divided byshaping members). The components labeled with the same referencenumerals in the electron beam exposure apparatus shown in FIG. 41 mayhave the same structures and functions as those shown in FIG. 1 and/orFIG. 33. In the following description, the structures, operations andfunctions that are different from those of the electron beam exposureapparatuses shown in FIGS. 1 and 33 are described.

The electron beam exposure apparatus 100 includes the exposure unit 150for performing a predetermined exposure process using electron beams fora wafer 44, and a controlling system 140 for controlling operations ofthe respective components included in the exposure unit 150.

The exposure unit 150 includes: a body 80 provided with a plurality ofexhaust holes 70; an electron beam shaping unit which can emit aplurality of electron beams and shape a cross-sectional shape of eachelectron beam into a desired shape; an illumination switching unit whichcan switch for each electron beam independently whether or not theelectron beam is cast onto the wafer 44; and an electron optical systemincluding a wafer projection system which can adjust the orientation andsize of a pattern image transferred onto the wafer 44. In addition, theexposure unit 150 includes a stage system having a wafer stage 46 onwhich the wafer 44 onto which the pattern is to be transferred byexposure can be placed and a wafer-stage driving unit 48 which can drivethe wafer stage 46.

The electron beam shaping unit includes an electron beam generator 10which can generate a plurality of electron beams, an anode 13 whichallows the generated electron beams to be radiated, a slit deflectingunit 15 for deflecting the electron beams after passing through theanode 13 independently of each other, a first multi-axis electron lens16 which can converge the electron beams to adjust focal points of theelectron beams independently of each other, a first lens-intensityadjuster 17 which can adjust the lens intensity of the first multi-axiselectron lens 16 for each of the electron beams independently of theother electron beams, and the BAA device 27 for dividing the electronbeams that have passed through the first multi-axis electron lens 16.

The illumination switching unit includes the BAA device 27 that switchesfor each of the electron beams whether or not the electron beam is to beincident on the wafer 44, and an electron beam blocking member 28 thathas a plurality of openings allowing the electron beams to passthere-through and can block the electron beams deflected by the BAAdevice 27. In this example, the BAA device 27 serves as a component ofthe electron beam shaping unit for shaping the cross-sectional shapes ofthe electron beams incident thereon and a component of the illuminationswitching unit. The openings included in the electron beam blockingmember 28 may have cross-sectional shapes each of which becomes wideralong the illumination direction of the electron beams in order to allowthe electron beams to efficiently pass.

The wafer projection system includes: a third multi-axis electron lens34 which can adjust the rotations of the electron beams to be incidentonto the wafer 44; a fourth multi-axis electron lens 36 which canconverge a plurality of electron beams independently of each other andadjust the reduction ratio of each electron beam to be incident onto thewafer 44; a deflecting unit 60 which can deflect a plurality of electronbeams independently of each other to direct desired portions on thewafer 44; and a coaxial lens 52 which has a first coil 40 and a secondcoil 54 and can serve as an objective lens for the wafer 44 byconverging a plurality of electron beams independently of each other. Inthis example, it is preferable that the coaxial lens 52 is arranged tobe closer to the wafer 44 than the multi-axis electron lens. Moreover,although the third multi-axis electron lens 34 and the fourth multi-axiselectron lens 36 are integrated with each other in this example, theymay be formed as separate components in an alternative example.

The controlling system 140 includes a general controller 130, amulti-axis electron lens controller 82, a coaxial lens controller 90, abackscattered electron processing unit 99, a wafer-stage controller 96and an individual controller 120 which can control exposure parametersfor each of the electron beams. The general controller 130 is, forexample, a work station and can control the respective controllersincluded in the individual controller 120. The multi-axis electron lenscontroller 82 controls currents to be respectively supplied to thefirst, third and fourth multi-axis electron lenses 16, 34 and 36. Thecoaxial electron lens controller 90 controls the amounts of currents tobe supplied to the first and second coils 40 and 54 of the coaxial lens52. The backscattered electron processing unit 99 receives a signalbased on the amount of backscattered electrons or secondary electronsdetected in a backscattered electron detector 50 and notify the generalcontroller 130 that the backscattered electron processing unit 99received the signal. The wafer-stage controller 96 controls thewafer-stage driving unit 48 so as to move the wafer stage 46 to apredetermined position.

The individual controller 120 includes an electron beam controller 80for controlling the electron beam generator 10, a lens-intensitycontroller 88 for controlling the lens-intensity adjuster 17, a BAAdevice controller 87 for controlling voltages to be applied todeflection electrodes included in the BAA device 27 and a deflectorcontroller 98 for controlling voltages to be applied to electrodesincluded in the deflectors of the deflecting unit 60.

Next, the operation of the electron beam exposure apparatus 100 in thepresent embodiment is described. First, the electron beam generator 10generates a plurality of electron beams. The generated electron beamspass through the anode 13 to enter the slit deflecting unit 15. The slitdeflecting unit 15 adjusts the incident positions on the BAA device 27onto which the electron beams after passing through the anode 13 areincident.

The first multi-axis electron lens 16 converges the electron beams afterpassing through the slit deflecting unit 15 independently of each other,thereby the focus adjustment of the electron beam with respect to theBAA device 27 can be performed for each electron beam. The firstlens-intensity adjuster 17 adjusts the lens intensity in each lensopening of the first multi-axis electron lens 16 in order to correct thefocus position of the corresponding electron beam incident on the lensopening. The electron beams after passing through the first multi-axiselectron lens 16 is incident on a plurality of aperture parts providedin the BAA device 27.

The BAA device controller 87 controls whether or not voltages areapplied to deflection electrodes provided in the vicinity of therespective apertures of the BAA device 27. Based on the voltages appliedto the deflection electrodes, the BAA device 27 switches for each of theelectron beams whether or not the electron beam is to be incident on thewafer 44. When the voltage is applied, the electron beam passing throughthe corresponding aperture is deflected. Thus, the deflected electronbeam cannot pass through a corresponding opening of the electron beamblocking member 28, so that it cannot be incident on the wafer 44. Whenthe voltage is not applied, the electron beam passing through thecorresponding aperture is shaped in the BAA device 27 without beingdeflected, so that it can pass through the corresponding opening of theelectron beam blocking member 28. Thus, the electron beam can beincident on the wafer 44.

The electron beam that has not been deflected by the BAA device 27passes through the electron beam blocking member 28 to be incident onthe third multi-axis electron lens 34. The third multi-axis electronlens 34 then adjusts the rotation of the electron beam image to beincident on the wafer 44. Moreover, the fourth multi-axis electron lens36 reduces the illumination diameter of the electron beam incidentthereon.

The deflector controller 98 controls a plurality of deflectors includedin the deflecting unit 60 independently of each other. The deflectingunit 60 deflects the electron beams incident on the deflectorsindependently of each other, in such a manner that the deflectedelectron beams are incident on the desired positions on the wafer 44.The electron beams after passing through the deflecting unit 60 aresubjected to the focus adjustment with respect to the wafer 44 by thecoaxial lens 52 having the first and second coils 40 and 54,respectively, so as to be made incident on the wafer 44.

During the exposure process, the wafer-stage controller 96 moves thewafer stage 48 in predetermined directions. The BAA device controller 87determines the apertures that allow the electron beams to passthere-through and performs an electric-power control for the respectiveapertures. In accordance with the movement of the wafer 44, theapertures allowing the electron beams to pass there-through are changedand the electron beams after passing through the apertures are deflectedby the deflecting unit 60. In this way, the wafer 44 is exposed to havea desired circuit pattern transferred.

The electron beam exposure apparatus 100 of the present embodimentconverges a plurality of electron beams independently of each other.Thus, although a cross over is formed for each electron beam, all theelectron beams as a whole do not have a cross over. Therefore, even in acase where the current density of each electron beam is increased, theelectron beam error that may cause a shift of the focus or position ofthe electron beam due to coulomb interaction can be greatly reduced.

FIGS. 42A and 42B show an exemplary arrangement of the BAA device 27. Asshown in FIG. 42A, the BAA device 27 includes a plurality of apertureparts 160 each having a plurality of apertures 166 allowing the electronbeams to pass, and deflecting electrode pads 162 and grounded electrodepads 164 both of which are used as connectors with the BAA controller 87shown in FIG. 41. It is desirable that each of the aperture parts 160and the corresponding lens opening of the first multi-axis electron lens16 are arranged coaxially. Also, it is preferable that the BAA device 27includes at least one dummy opening 205 (see FIG. 41) through which noelectron beam passes provided in the surrounding area of the apertureparts 160. In this case, the inductance of the exhaustion in the body 8can be reduced, allowing the efficient reduction of the pressure in thebody 8.

FIG. 42B is atop view of the aperture part 160. As described above, theaperture part 160 includes a plurality of apertures 166. It ispreferable that the aperture 166 has a rectangular shape. The electronbeam incident on each aperture part 160 is divided and shaped so thatthe divided electron beams have cross-sectional shapes in accordancewith the shapes of apertures 166. As described above, since the electronbeam exposure apparatus 100 of the present embodiment includes the BAAdevice 27, the electron beam exposure apparatus 100 can divide each ofthe electron beams generated by the electron beam generator 10 into aplurality of beams so that the wafer 44 is exposed by the dividedelectron beams. Thus, it is possible to make a number of electron beamsincident on the wafer 44, thereby it takes an extremely short time toexpose the pattern onto the wafer 44.

FIG. 43A is a top view of the third multi-axis electron lens 34. Pleasenote that the fourth multi-axis electron lens 36 may have the samestructure as that of the third multi-axis electron lens 34. Therefore,in the following description, the structure of the third multi-axiselectron lens 34 is described as a typical example.

As shown in FIG. 43A, the third multi-axis electron lens 34 includes acoil part 200 for generating a magnetic field and a lens part 202. Thelens part 202 has a plurality of lens regions 206 in each of which aplurality of lens openings through which the electron beams pass areprovided. It is desirable to coaxially arrange the lens region 206 ofthe lens part 202, the corresponding lens opening of the firstmulti-axis electron lens 16 and the corresponding aperture part 160 ofthe BAA device 27.

FIG. 43B shows each lens region 206. The lens region 206 has a pluralityof lens openings 204. It is desirable to arrange each lens opening 204,a corresponding one of the apertures 166 provided in the aperture part160 of the BAA device 27, and a corresponding one of the deflectors 184included in the deflector array 180 coaxially. Moreover, the lens part202 preferably includes at least one dummy opening 205 describedreferring to FIG. 8-11. In this case, it is preferable that the dummyopening 205 is provided on the outer side of the region where aplurality of lens regions 206 are provided.

FIG. 44A is a top view of the deflecting unit 60. The deflecting unit 60includes a substrate 186, a plurality of deflector arrays 180 and aplurality of deflecting electrode pads 182. The deflector arrays 180 aredesirably arranged at the center of the substrate 186, while thedeflecting electrode pads 182 are provided in the peripheral region ofthe substrate 186. It is also desirable that each of the deflectorarrays 180, the corresponding aperture part 160 of the BAA device 27,and the corresponding lens regions 206 of the third and fourthmulti-axis electron lenses 34 and 36 are arranged coaxially. Moreover,the deflecting electrode pads 182 are electrically connected to thedeflector controller 98 (shown in FIG. 41) via a connector such as aprobe card or a pogo pin array.

FIG. 44B shows an example of the deflector array 180. The deflectorarray 180 has a plurality of deflectors 184 each formed by a pluralityof deflecting electrodes and an opening. It is desirable to arrange thedeflector 184 coaxially with a corresponding one of the apertures 166 inthe aperture part 160 of the BAA device 27, and corresponding ones ofthe lens openings 204 provided in the lens regions 206 of the third andfourth multi-axis electron lenses 34 and 36.

FIGS. 45A through 45G illustrate a fabrication process of the lens part202 included in the multi-axis electron lens according to an embodimentof the present invention. First, a conductive substrate 300 is prepared.As shown in FIG. 45A, a photosensitive layer 302 is applied onto theconductive substrate 300. The photosensitive layer 302 is preferablyformed by spin-coating or making a thick resist film having apredetermined thickness adhere to the substrate 300, for example. Thephotosensitive layer 302 is formed to have a thickness equal to orthicker than the thickness of the lens part 202.

FIG. 45B shows an exposure process in which a predetermined pattern isformed by exposure and the first removal process in which apredetermined area is removed. The predetermined pattern is formed basedon the diameter of the lens part 202 and the pattern of the lensopenings 204 through which a plurality of electron beams pass, referringto FIGS. 8-11, 39, 43A and 43B. More specifically, the predeterminedpattern is determined by the diameter of the lens part 202 and thediameter and position of the lens opening 204. Then, a lens-forming mold304 and a lens-opening-forming mold 306 to be used for forming the lenspart 202 and the lens opening 204 in an electro forming processdescribed later are formed based on the diameter of the lens part 202and the diameter and position of the lens opening 204, respectively, bythe exposure process and the first removal process.

The predetermined pattern may be further formed based on a pattern ofthe dummy opening through which no electron beam passes. In this case, adummy-opening-forming mold to be used for forming the dummy opening maybe formed by the exposure process and the first removal process. Thedummy-opening-forming mold may be formed to have a different diameterfrom that of the lens-opening forming mold.

In the exposure process, it is preferable to use an exposure methodcorresponding to an aspect ratio that is a ratio of the opening diameterto the opening depth of the lens opening 204. The opening diameter ofthe lens opening 204 is preferably in the range of 0.1 mm to 2 mm, whilethe opening depth is preferably in the range of 5 mm to 50 mm. In thisexample, the lens opening has an opening diameter of about 0.5 mm and anopening depth of about 20 mm, that is, the aspect ratio is about 40.Therefore, it is preferable to use an X-ray exposure method that has ahigh transmissivity for the photosensitive layer and therefore caneasily form a high aspect-ratio pattern. In this case, thephotosensitive layer 302 is preferably a positive or negative typephotoresist for X-ray exposure, and is exposed with an X-ray exposuremask having a pattern corresponding to the patterns of the lens-formingmold 304 and the lens-opening-forming mold 306. Then, an exposed area ina case of the positive type photosensitive layer 302 or an area that isnot exposed in a case of the negative type photosensitive layer 302 isremoved, thereby forming the lens-forming mold 304 and thelens-opening-forming mold 306 are obtained.

In a process shown in FIG. 45C, the first magnetic conductive member 210a is formed by electro forming. The first magnetic conductive member 210a is formed of, for example, nickel alloy to have a thickness of about 5mm by electroplating using the conductive substrate 300 as an electrode.

In a process shown in FIG. 45D, the non-magnetic conductive member 242is formed by electro forming. The non-magnetic conductive member 242 isformed of, for example, copper to have a thickness of about 5-20 mm byelectroplating using the first magnetic conductive member 210 a as anelectrode.

The second magnetic conductive member 210 b is then formed by electroforming in a process shown in FIG. 45E. The second magnetic conductivemember 210 b is formed of, for example, nickel alloy to have a thicknessof about 5-20 mm by electroplating using the non-magnetic conductivemember 242 as an electrode.

The photosensitive layer 302 is then removed in the second removalprocess shown in FIG. 45F. In the second removal process, the remainingparts of the photosensitive layer 302, that is, the lens-forming mold304 and the lens-opening-forming mold 306 are removed. As a result, thelens openings 204 that have a plurality of first openings included inthe first magnetic conductive member 210 a, a plurality of through holesincluded in the non-magnetic conductive member that are arrangedcoaxially with the first openings, and a plurality of second openingsincluded in the second magnetic conductive member 210 b that arearranged coaxially with the first openings and the through holes areformed, respectively.

FIG. 45G illustrates a peeling process in which the conductive substrate300 is peeled off. By peeling the conductive substrate 300 off, the lenspart 202 is obtained. The conductive substrate 300 may be removed byusing a drug solution that can remove the conductive substrate 300 withsubstantially no reaction with the first and second magnetic conductivemembers 210 a and 210 b and the non-magnetic conductive member 242.

FIGS. 46A through 46E illustrate processes for forming the projections218. FIG. 46A shows the first lens magnetic conductive member 210 aformed on the conductive substrate 300 in the process shown in FIG. 45C.On the first lens magnetic conductive member 210 a, thelens-opening-forming molds 306 are formed so as to correspond topositions at which the projections 218 described with reference to FIG.14B are to be formed. Then, as shown in FIG. 46C, first projections 218a, the non-magnetic member 242 and second projections 218 b are formedby a similar process to that described in FIGS. 45C through 45E.

The lens-opening-forming molds 306 are then removed and thereafteropening areas where the lens-opening-forming molds 306 are removed arefilled with a filling member 314. It is desirable to form the fillingmember 34 from material that can be removed selectively with respect tomaterials for the magnetic conductive members 210, the projections 218and the non-magnetic conductive member 242. It is also desirable thatthe filling member 314 is formed to have such a thickness that thelevels of the filling member 314 and the second projections 218 aresubstantially the same. After the formation of the filling member 314,the lens-opening-forming molds 306 are formed again in a similar mannerto the processes described before, thereby forming the second magneticconductive member 210 b. Then, the lens-opening-forming molds 306, thefilling member 314 and the conductive substrate 300 are removed, asshown in FIG. 46E, so that the lens part 202 is obtained.

The first and second projections 218 a and 218 b may be formed frommaterial having a different magnetic permeability from the material forthe lens magnetic conductive members 210. Moreover, the cut portions maybe formed by forming lens-opening-forming molds having a patternobtained by reversing the lens-opening-forming molds 306 as shown inFIG. 46B, and then etching the lens magnetic conductive members 210 byusing the lens-opening-forming molds as a mask.

FIGS. 47A and 47B illustrate another example of the fabrication methodof the lens part 202. After the formation of the second magneticconductive member has been completed, the formation of the firstmagnetic conductive member, the formation of the non-magnetic conductivemember, and the formation of the second magnetic conductive member areperformed a plurality of times repeatedly. Then, by performing thesecond removal process and the peeling process, a lens block 320including a plurality of lens parts 202 is obtained, as shown in FIG.47A. The individual lens parts 202 may be obtained by slicing the lensblock 320, as shown in FIG. 47A. Alternatively, the lens parts 202 maybe obtained by forming the lens block 320 so as to include separationmembers 322 between the lens parts 202 and then removing only theseparation members 322 by using a drug solution that can remove theseparation members 322 with substantially no reaction with thenon-magnetic conductive member 242 and the second magnetic conductivemember 210 b. In these examples, the photosensitive layer 302 isdesirably formed to have a thickness thicker than the thickness of thelens block 320.

FIGS. 48A through 48C illustrate a fixing process for fixing the coilpart 200 and the lens part 202. FIG. 48A shows the coil part 200 forgenerating the magnetic field. It is preferable that the coil part 200has an inner diameter corresponding to the diameter of the lens part 202so as to have an annular shape. The coil part 200 has the coil magneticconductive member 212 provided in the surrounding area of the coil 214that can generate the magnetic field and a space 310. The space 310 mayinclude a non-magnetic conductive member or be filled with thenon-magnetic conductive member. It is preferable that the coil magneticconductive member 212 and the coil 214 are formed by fine machining, forexample. The coil part 200 is formed by joining the magnetic conductivemember 212 and the coil 214 by fine machining, such as screwing, weldingor bonding. The coil magnetic conductive member 212 is preferably formedfrom material having a different magnetic permeability from that of thematerial for the lens magnetic conductive member 210.

FIG. 48B shows a process for forming a support 312 used for fixing thelens part 202 to the coil part 200. After the coil part 200 has beenformed, the support 312 formed of non-magnetic conductive material isjoined to the coil part 200 by fine machining, such as screwing, weldingor bonding. It is desirable to arrange the support 312 at such aposition that the support 312 supports the lens part 202 so as to fitthe space 310 of the coil part 200 to the non-magnetic conductive member242 of the lens part 202 in the fixing process described later. Thesupport 312 may be a single annular member or include a plurality ofconvex members that supports the lens part 202 as a plurality ofsupporting points. Moreover, the support 312 may be formed integrallywith the magnetic conductive member 212. More specifically, the magneticconductive member 312 may be formed to include a convex portion servingas the support 312. In this case, it is desirable that the support 312is formed to have such a dimension that the support 312 has no effect onthe magnetic field generated in the lens opening 204 by the first andsecond lens magnetic conductive members 210 a and 210 b.

FIG. 48C shows the fixing process for fixing the coil part 200 and thelens part 202 by means of the support 312. The lens part 202 ispreferably joined to be fixed to the coil part 200 by bonding or fittingthe space 310 of the coil part 200 to the non-magnetic conductive member242 or meshing the space 310 with the non-magnetic conductive member242. The support 312 may be removed after the lens part 202 is fixed tothe coil part 200.

FIG. 49 is a flowchart of a fabrication process of a semiconductordevice according to an embodiment of the present invention, in which thesemiconductor device is fabricated from a wafer. In Step S10, thefabrication process starts. First, photoresist is applied onto an uppersurface of the wafer 44 in Step S12. The wafer 44 on which thephotoresist is applied is then placed on the wafer stage 46 in theelectron beam exposure apparatus 100, referring to FIGS. 1 and 17. Thewafer 44 is exposed to have a pattern image transferred thereon by beingilluminated with the electron beams by the focus adjustment process inwhich the focus adjustment of the electron beam is performed for each ofthe electron beams independently of other electron beams by means of thefirst, second, third, and fourth multi-axis electron lenses 16, 24, 34and 36, and the illumination switching process in which it is switchedby the blanking electrode array 26 for each electron beam independentlyof other electron beams whether or not the electron beam is to beincident on the wafer 44, as described before referring to FIGS. 1, 33and 41.

The wafer 44 exposed in Step S14 is then immersed into developingsolution to be developed, and thereafter unnecessary resist is removed(Step S16). In Step S18, a silicon substrate, an insulating layer or aconductive layer in areas of the wafer where the photoresist is removedare etched by anisotropic etching using plasma. In Step S20, impuritiessuch as boron or arsenic ions are doped into the wafer in order tofabricate a semiconductor device such as a transistor or a diode. InStep S22, the impurities are activated by annealing. In Step S24, thewafer 44 is cleaned by a cleaning solution to remove organic contaminantor metal contaminant on the wafer. Then, a conductive layer and aninsulating layer are deposited to form a wiring layer and an insulatorbetween the wirings. By appropriately combining the processes in StepsS12 to S26 and repeating the combined processes, it is possible tofabricate the semiconductor device having an isolation region, a deviceregion and wirings on the wafer. In Step S28, the wafer on which adesired circuit has been formed is cut, and then assembly of chips isperformed. In Step S30, the fabrication flow of the semiconductor deviceis finished.

As is apparent from the above description, according to the presentinvention, a plurality of electron beams can be converged independentlyof each other and can be controlled for each of the electron beamswhether or not to be incident on the wafer, by including the multi-axiselectron lens and the illumination switching unit. Thus, since theelectron beams can be controlled independently without cross over, it ispossible to greatly improve throughput.

Although the present invention has been described by way of exemplaryembodiments, it should be understood that those skilled in the art mightmake many changes and substitutions without departing from the spiritand the scope of the present invention which is defined only by theappended claims.

What is claimed is:
 1. An electron beam exposure apparatus for exposinga wafer with a plurality of electron beams, comprising a multi-axiselectron lens having a plurality of lens openings operable to convergesaid plurality of electron beams independently of each other by allowingsaid plurality of electron beams to pass therethrough, respectively,said plurality of lens openings having different shapes.
 2. An electronbeam exposure apparatus as claimed in claim 1, wherein said multi-axiselectron lens includes a plurality of magnetic conductive members havinga plurality of openings arranged to be substantially parallel to eachother, said plurality of openings forming said lens openings.
 3. Anelectron beam exposure apparatus as claimed in claim 2, wherein saidmagnetic conductive members include said openings having differentsizes.
 4. An electron beam exposure apparatus as claimed in claim 2,wherein at least one of said plurality of magnetic conductive membersincludes cut portions provided in outer peripheries of said openings. 5.An electron beam exposure apparatus as claimed in claim 4, wherein saidcut portions have different sizes.
 6. An electron beam exposureapparatus as claimed in claim 2, wherein at least one of said magneticconductive members includes a magnetic conductive projection provided ona surface thereof between a predetermined one of said openings andanother opening adjacent to said predetermined opening, said magneticconductive projection projecting from said surface of said at least oneof said magnetic conductive members.
 7. An electron beam exposureapparatus as claimed in claim 2, further comprising a lens-intensityadjuster including: a substrate provided to be substantially parallel tosaid multi-axis electron lens; and a lens-intensity adjusting unit,provided on said substrate, operable to adjust the lens intensity ofsaid multi-axis electron lens applied to said electron beams passingthrough said lens openings, respectively.
 8. An electron beam exposureapparatus as claimed in claim 7, wherein said lens-intensity adjustingunit includes an adjusting electrode provided to surround said electronbeams from said substrate to said lens opening, said adjusting electrodebeing insulated from said magnetic conductive members.
 9. An electronbeam exposure apparatus as claimed in claim 7, wherein saidlens-intensity adjusting unit includes a plurality of adjustingelectrodes provided to surround said electron beams, respectively, fromsaid substrate to said lens opening.
 10. An electron beam exposureapparatus as claimed in claim 9, wherein said lens-intensity adjustingunit further includes a means operable to apply different voltages tosaid plurality of adjusting electrodes.
 11. An electron beam exposureapparatus as claimed in claim 7, wherein said lens-intensity adjustingunit further includes an adjusting coil operable to adjust magneticfield intensities in said lens openings, said adjusting coil beingprovided to surround said electron beams from said substrate along adirection in which said electron beams are radiated.
 12. An electronbeam exposure apparatus as claimed in claim 2, wherein said multi-axiselectron lens further includes a non-magnetic conductive member having aplurality of through holes, said non-magnetic conductive member beingprovided between said plurality of magnetic conductive members, saidplurality of openings of said magnetic conductive members and saidplurality of through holes forming together said plurality of lensopenings.
 13. An electron beam exposure apparatus as claimed in claim 2,wherein said multi-axis electron lens further includes a coil parthaving a coil provided in an area surrounding said magnetic conductivemembers for generating a magnetic field and a coil magnetic conductivemember provided in an area surrounding said coil.
 14. An electron beamexposure apparatus as claimed in claim 13, wherein said coil magneticconductive member is formed from a material having a different magneticpermeability from that of a material for said plurality of magneticconductive members.
 15. An electron beam exposure apparatus as claimedin claim 1, further comprising at least one further multi-axis electronlens operable to reduce cross sections of said electron beams.
 16. Anelectron beam exposure apparatus as claimed in claim 1, furthercomprising an electron beam shaping unit that comprises: a first shapingmember having a plurality of first shaping openings operable to shapesaid plurality of electron beams; a first shaping-deflecting unitoperable to deflect said plurality of electron beams after passingthrough said first shaping member, independently of each other; and asecond shaping member having a plurality of second shaping openingsoperable to shape said plurality of electron beams after passing throughsaid first shaping-deflecting unit to have desired shapes.
 17. Anelectron beam exposure apparatus as claimed in claim 16, wherein saidelectron beam shaping unit further includes a second shaping-deflectingunit operable to deflect said plurality of electron beams deflected bysaid first shaping-deflecting unit independently of each other toward adirection substantially perpendicular to a surface of said wafer ontowhich said electron beams are incident, wherein said electron beamshaping unit allows said plurality of electron beams deflected by saidsecond shaping-deflecting unit to pass through said second shapingmember so as to shape said electron beams to have said desired shapes.18. An electron beam exposure apparatus as claimed in claim 17, whereinsaid second shaping member includes a plurality of shaping-memberillumination areas onto which said electron beams deflected by thesecond shaping-deflecting unit are incident, and said second shapingmember includes said second shaping openings and other openings havingdifferent sizes from sizes of said second shaping openings in saidshaping-member illumination area.
 19. An electron beam exposureapparatus as claimed in claim 16, further comprising: a plurality ofelectron guns operable to generate said plurality of electron beams; anda further multi-axis electron lens operable to converge said pluralityof electron beams generated by said plurality of electron guns to makesaid converged electron beams incident on said first shaping member,wherein said first shaping member divides said electron beams afterpassing through said further multi-axis electron lens.
 20. An electronbeam exposure apparatus as claimed in claim 1, wherein a plurality ofmulti-axis electron lenses having said lens openings are provided. 21.An electron beam exposure apparatus as claimed in claim 1, wherein saidmulti-axis electron lens further includes a plurality of dummy openingsthrough which no electron beam passes.
 22. An electron beam exposureapparatus as claimed in claim 21, wherein said plurality of dummyopenings are provided in outer peripheries of an area where saidplurality of lens openings are arranged.
 23. An electron lens forconverging a plurality of electron beams independently of each other,comprising a plurality of magnetic conductive members arranged to besubstantially parallel to each other, said magnetic conductive membershaving a plurality of openings, wherein said plurality of openings ofsaid magnetic conductive members form a plurality of lens openingsallowing said plurality of electron beams to pass therethrough,respectively, to converge said electron beams independently of eachother, said lens openings having different shapes.
 24. A fabricationmethod of a semiconductor device on a wafer, comprising: performingfocus adjustments for said plurality of electron beams independently ofeach other by using a multi-axis electron lens having a plurality oflens openings having different shapes that allow a plurality of electronbeams to pass therethrough, respectively, to converge said electronbeams independently of each other; and exposing a pattern onto saidwafer by illuminating said wafer with said plurality of electron beams.